Add HPack dynamic compression (#20058)

src/Servers/Kestrel/Core/ref/Microsoft.AspNetCore.Server.Kestrel.Core.netcoreapp.cs

@@ -127,6 +127,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core
     {
         public KestrelServerOptions() { }
         public bool AddServerHeader { [System.Runtime.CompilerServices.CompilerGeneratedAttribute] get { throw null; } [System.Runtime.CompilerServices.CompilerGeneratedAttribute] set { } }
+        public bool AllowResponseHeaderCompression { [System.Runtime.CompilerServices.CompilerGeneratedAttribute] get { throw null; } [System.Runtime.CompilerServices.CompilerGeneratedAttribute] set { } }
         public bool AllowSynchronousIO { [System.Runtime.CompilerServices.CompilerGeneratedAttribute] get { throw null; } [System.Runtime.CompilerServices.CompilerGeneratedAttribute] set { } }
         public System.IServiceProvider ApplicationServices { [System.Runtime.CompilerServices.CompilerGeneratedAttribute] get { throw null; } [System.Runtime.CompilerServices.CompilerGeneratedAttribute] set { } }
         public Microsoft.AspNetCore.Server.Kestrel.KestrelConfigurationLoader ConfigurationLoader { [System.Runtime.CompilerServices.CompilerGeneratedAttribute] get { throw null; } [System.Runtime.CompilerServices.CompilerGeneratedAttribute] set { } }

src/Servers/Kestrel/Core/src/CoreStrings.resx

@@ -599,4 +599,7 @@ For more information on configuring HTTPS see https://go.microsoft.com/fwlink/?l
   <data name="TransportNotFound" xml:space="preserve">
     <value>Unable to resolve service for type 'Microsoft.AspNetCore.Connections.IConnectionListenerFactory' while attempting to activate 'Microsoft.AspNetCore.Server.Kestrel.Core.KestrelServer'.</value>
   </data>
+  <data name="GreaterThanOrEqualToZeroRequired" xml:space="preserve">
+    <value>A value greater than or equal to zero is required.</value>
+  </data>
 </root>

src/Servers/Kestrel/Core/src/Http2Limits.cs

@@ -39,9 +39,9 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core
         }
 
         /// <summary>
-        /// Limits the size of the header compression table, in octets, the HPACK decoder on the server can use.
+        /// Limits the size of the header compression tables, in octets, the HPACK encoder and decoder on the server can use.
         /// <para>
-        /// Value must be greater than 0, defaults to 4096
+        /// Value must be greater than or equal to 0, defaults to 4096
         /// </para>
         /// </summary>
         public int HeaderTableSize
@@ -49,9 +49,9 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core
             get => _headerTableSize;
             set
             {
-                if (value <= 0)
+                if (value < 0)
                 {
-                    throw new ArgumentOutOfRangeException(nameof(value), value, CoreStrings.GreaterThanZeroRequired);
+                    throw new ArgumentOutOfRangeException(nameof(value), value, CoreStrings.GreaterThanOrEqualToZeroRequired);
                 }
 
                 _headerTableSize = value;

src/Servers/Kestrel/Core/src/Internal/Http2/HPackHeaderWriter.cs

@@ -4,7 +4,6 @@
 using System;
 using System.Net.Http;
 using System.Net.Http.HPack;
-using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http;
 
 namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2
 {
@@ -13,57 +12,105 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2
         /// <summary>
         /// Begin encoding headers in the first HEADERS frame.
         /// </summary>
-        public static bool BeginEncodeHeaders(int statusCode, Http2HeadersEnumerator headersEnumerator, Span<byte> buffer, out int length)
+        public static bool BeginEncodeHeaders(int statusCode, HPackEncoder hpackEncoder, Http2HeadersEnumerator headersEnumerator, Span<byte> buffer, out int length)
         {
-            if (!HPackEncoder.EncodeStatusHeader(statusCode, buffer, out var statusCodeLength))
+            length = 0;
+
+            if (!hpackEncoder.EnsureDynamicTableSizeUpdate(buffer, out var sizeUpdateLength))
             {
                 throw new HPackEncodingException(SR.net_http_hpack_encode_failure);
             }
+            length += sizeUpdateLength;
+
+            if (!EncodeStatusHeader(statusCode, hpackEncoder, buffer.Slice(length), out var statusCodeLength))
+            {
+                throw new HPackEncodingException(SR.net_http_hpack_encode_failure);
+            }
+            length += statusCodeLength;
 
             if (!headersEnumerator.MoveNext())
             {
-                length = statusCodeLength;
                 return true;
             }
 
             // We're ok with not throwing if no headers were encoded because we've already encoded the status.
             // There is a small chance that the header will encode if there is no other content in the next HEADERS frame.
-            var done = EncodeHeaders(headersEnumerator, buffer.Slice(statusCodeLength), throwIfNoneEncoded: false, out var headersLength);
-            length = statusCodeLength + headersLength;
-
+            var done = EncodeHeadersCore(hpackEncoder, headersEnumerator, buffer.Slice(length), throwIfNoneEncoded: false, out var headersLength);
+            length += headersLength;
             return done;
         }
 
         /// <summary>
         /// Begin encoding headers in the first HEADERS frame.
         /// </summary>
-        public static bool BeginEncodeHeaders(Http2HeadersEnumerator headersEnumerator, Span<byte> buffer, out int length)
+        public static bool BeginEncodeHeaders(HPackEncoder hpackEncoder, Http2HeadersEnumerator headersEnumerator, Span<byte> buffer, out int length)
         {
+            length = 0;
+
+            if (!hpackEncoder.EnsureDynamicTableSizeUpdate(buffer, out var sizeUpdateLength))
+            {
+                throw new HPackEncodingException(SR.net_http_hpack_encode_failure);
+            }
+            length += sizeUpdateLength;
+
             if (!headersEnumerator.MoveNext())
             {
-                length = 0;
                 return true;
             }
 
-            return EncodeHeaders(headersEnumerator, buffer, throwIfNoneEncoded: true, out length);
+            var done = EncodeHeadersCore(hpackEncoder, headersEnumerator, buffer.Slice(length), throwIfNoneEncoded: true, out var headersLength);
+            length += headersLength;
+            return done;
         }
 
         /// <summary>
         /// Continue encoding headers in the next HEADERS frame. The enumerator should already have a current value.
         /// </summary>
-        public static bool ContinueEncodeHeaders(Http2HeadersEnumerator headersEnumerator, Span<byte> buffer, out int length)
+        public static bool ContinueEncodeHeaders(HPackEncoder hpackEncoder, Http2HeadersEnumerator headersEnumerator, Span<byte> buffer, out int length)
         {
-            return EncodeHeaders(headersEnumerator, buffer, throwIfNoneEncoded: true, out length);
+            return EncodeHeadersCore(hpackEncoder, headersEnumerator, buffer, throwIfNoneEncoded: true, out length);
         }
 
-        private static bool EncodeHeaders(Http2HeadersEnumerator headersEnumerator, Span<byte> buffer, bool throwIfNoneEncoded, out int length)
+        private static bool EncodeStatusHeader(int statusCode, HPackEncoder hpackEncoder, Span<byte> buffer, out int length)
+        {
+            switch (statusCode)
+            {
+                case 200:
+                case 204:
+                case 206:
+                case 304:
+                case 400:
+                case 404:
+                case 500:
+                    // Status codes which exist in the HTTP/2 StaticTable.
+                    return HPackEncoder.EncodeIndexedHeaderField(H2StaticTable.StatusIndex[statusCode], buffer, out length);
+                default:
+                    const string name = ":status";
+                    var value = StatusCodes.ToStatusString(statusCode);
+                    return hpackEncoder.EncodeHeader(buffer, H2StaticTable.Status200, HeaderEncodingHint.Index, name, value, out length);
+            }
+        }
+
+        private static bool EncodeHeadersCore(HPackEncoder hpackEncoder, Http2HeadersEnumerator headersEnumerator, Span<byte> buffer, bool throwIfNoneEncoded, out int length)
         {
             var currentLength = 0;
             do
             {
-                if (!EncodeHeader(headersEnumerator.KnownHeaderType, headersEnumerator.Current.Key, headersEnumerator.Current.Value, buffer.Slice(currentLength), out int headerLength))
+                var staticTableId = headersEnumerator.HPackStaticTableId;
+                var name = headersEnumerator.Current.Key;
+                var value = headersEnumerator.Current.Value;
+
+                var hint = ResolveHeaderEncodingHint(staticTableId, name);
+
+                if (!hpackEncoder.EncodeHeader(
+                    buffer.Slice(currentLength),
+                    staticTableId,
+                    hint,
+                    name,
+                    value,
+                    out var headerLength))
                 {
-                    // The the header wasn't written and no headers have been written then the header is too large.
+                    // If the header wasn't written, and no headers have been written, then the header is too large.
                     // Throw an error to avoid an infinite loop of attempting to write large header.
                     if (currentLength == 0 && throwIfNoneEncoded)
                     {
@@ -79,79 +126,48 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2
             while (headersEnumerator.MoveNext());
 
             length = currentLength;
-
             return true;
         }
 
-        private static bool EncodeHeader(KnownHeaderType knownHeaderType, string name, string value, Span<byte> buffer, out int length)
+        private static HeaderEncodingHint ResolveHeaderEncodingHint(int staticTableId, string name)
         {
-            var hPackStaticTableId = GetResponseHeaderStaticTableId(knownHeaderType);
-
-            if (hPackStaticTableId == -1)
+            HeaderEncodingHint hint;
+            if (IsSensitive(staticTableId, name))
             {
-                return HPackEncoder.EncodeLiteralHeaderFieldWithoutIndexingNewName(name, value, buffer, out length);
+                hint = HeaderEncodingHint.NeverIndex;
+            }
+            else if (IsNotDynamicallyIndexed(staticTableId))
+            {
+                hint = HeaderEncodingHint.IgnoreIndex;
             }
             else
             {
-                return HPackEncoder.EncodeLiteralHeaderFieldWithoutIndexing(hPackStaticTableId, value, buffer, out length);
+                hint = HeaderEncodingHint.Index;
             }
+
+            return hint;
         }
 
-        private static int GetResponseHeaderStaticTableId(KnownHeaderType responseHeaderType)
+        private static bool IsSensitive(int staticTableIndex, string name)
         {
-            switch (responseHeaderType)
+            // Set-Cookie could contain sensitive data.
+            if (staticTableIndex == H2StaticTable.SetCookie)
             {
-                case KnownHeaderType.CacheControl:
-                    return H2StaticTable.CacheControl;
-                case KnownHeaderType.Date:
-                    return H2StaticTable.Date;
-                case KnownHeaderType.TransferEncoding:
-                    return H2StaticTable.TransferEncoding;
-                case KnownHeaderType.Via:
-                    return H2StaticTable.Via;
-                case KnownHeaderType.Allow:
-                    return H2StaticTable.Allow;
-                case KnownHeaderType.ContentType:
-                    return H2StaticTable.ContentType;
-                case KnownHeaderType.ContentEncoding:
-                    return H2StaticTable.ContentEncoding;
-                case KnownHeaderType.ContentLanguage:
-                    return H2StaticTable.ContentLanguage;
-                case KnownHeaderType.ContentLocation:
-                    return H2StaticTable.ContentLocation;
-                case KnownHeaderType.ContentRange:
-                    return H2StaticTable.ContentRange;
-                case KnownHeaderType.Expires:
-                    return H2StaticTable.Expires;
-                case KnownHeaderType.LastModified:
-                    return H2StaticTable.LastModified;
-                case KnownHeaderType.AcceptRanges:
-                    return H2StaticTable.AcceptRanges;
-                case KnownHeaderType.Age:
-                    return H2StaticTable.Age;
-                case KnownHeaderType.ETag:
-                    return H2StaticTable.ETag;
-                case KnownHeaderType.Location:
-                    return H2StaticTable.Location;
-                case KnownHeaderType.ProxyAuthenticate:
-                    return H2StaticTable.ProxyAuthenticate;
-                case KnownHeaderType.RetryAfter:
-                    return H2StaticTable.RetryAfter;
-                case KnownHeaderType.Server:
-                    return H2StaticTable.Server;
-                case KnownHeaderType.SetCookie:
-                    return H2StaticTable.SetCookie;
-                case KnownHeaderType.Vary:
-                    return H2StaticTable.Vary;
-                case KnownHeaderType.WWWAuthenticate:
-                    return H2StaticTable.WwwAuthenticate;
-                case KnownHeaderType.AccessControlAllowOrigin:
-                    return H2StaticTable.AccessControlAllowOrigin;
-                case KnownHeaderType.ContentLength:
-                    return H2StaticTable.ContentLength;
-                default:
-                    return -1;
+                return true;
             }
+            if (string.Equals(name, "Content-Disposition", StringComparison.OrdinalIgnoreCase))
+            {
+                return true;
+            }
+
+            return false;
+        }
+
+        private static bool IsNotDynamicallyIndexed(int staticTableIndex)
+        {
+            // Content-Length is added to static content. Content length is different for each
+            // file, and is unlikely to be reused because of browser caching.
+            return staticTableIndex == H2StaticTable.ContentLength;
         }
     }
 }

src/Servers/Kestrel/Core/src/Internal/Http2/Http2Connection.cs

@@ -87,7 +87,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2
                 httpLimits.MinResponseDataRate,
                 context.ConnectionId,
                 context.MemoryPool,
-                context.ServiceContext.Log);
+                context.ServiceContext);
 
             var inputOptions = new PipeOptions(pool: context.MemoryPool,
                 readerScheduler: context.ServiceContext.Scheduler,
@@ -743,6 +743,15 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2
                     }
                 }
 
+                // Maximum HPack encoder size is limited by Http2Limits.HeaderTableSize, configured max the server.
+                //
+                // Note that the client HPack decoder doesn't care about the ACK so we don't need to lock sending the
+                // ACK and updating the table size on the server together.
+                // The client will wait until a size agreed upon by it (sent in SETTINGS_HEADER_TABLE_SIZE) and the
+                // server (sent as a dynamic table size update in the next HEADERS frame) is received before applying
+                // the new size.
+                _frameWriter.UpdateMaxHeaderTableSize(Math.Min(_clientSettings.HeaderTableSize, (uint)Limits.Http2.HeaderTableSize));
+
                 return ackTask.AsTask();
             }
             catch (Http2SettingsParameterOutOfRangeException ex)

src/Servers/Kestrel/Core/src/Internal/Http2/Http2FrameWriter.cs

@@ -38,6 +38,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2
         private readonly ITimeoutControl _timeoutControl;
         private readonly MinDataRate _minResponseDataRate;
         private readonly TimingPipeFlusher _flusher;
+        private readonly HPackEncoder _hpackEncoder;
 
         private uint _maxFrameSize = Http2PeerSettings.MinAllowedMaxFrameSize;
         private byte[] _headerEncodingBuffer;
@@ -55,7 +56,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2
             MinDataRate minResponseDataRate,
             string connectionId,
             MemoryPool<byte> memoryPool,
-            IKestrelTrace log)
+            ServiceContext serviceContext)
         {
             // Allow appending more data to the PipeWriter when a flush is pending.
             _outputWriter = new ConcurrentPipeWriter(outputPipeWriter, memoryPool, _writeLock);
@@ -63,12 +64,22 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2
             _http2Connection = http2Connection;
             _connectionOutputFlowControl = connectionOutputFlowControl;
             _connectionId = connectionId;
-            _log = log;
+            _log = serviceContext.Log;
             _timeoutControl = timeoutControl;
             _minResponseDataRate = minResponseDataRate;
-            _flusher = new TimingPipeFlusher(_outputWriter, timeoutControl, log);
+            _flusher = new TimingPipeFlusher(_outputWriter, timeoutControl, serviceContext.Log);
             _outgoingFrame = new Http2Frame();
             _headerEncodingBuffer = new byte[_maxFrameSize];
+
+            _hpackEncoder = new HPackEncoder(serviceContext.ServerOptions.AllowResponseHeaderCompression);
+        }
+
+        public void UpdateMaxHeaderTableSize(uint maxHeaderTableSize)
+        {
+            lock (_writeLock)
+            {
+                _hpackEncoder.UpdateMaxHeaderTableSize(maxHeaderTableSize);
+            }
         }
 
         public void UpdateMaxFrameSize(uint maxFrameSize)
@@ -175,7 +186,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2
                     _headersEnumerator.Initialize(headers);
                     _outgoingFrame.PrepareHeaders(headerFrameFlags, streamId);
                     var buffer = _headerEncodingBuffer.AsSpan();
-                    var done = HPackHeaderWriter.BeginEncodeHeaders(statusCode, _headersEnumerator, buffer, out var payloadLength);
+                    var done = HPackHeaderWriter.BeginEncodeHeaders(statusCode, _hpackEncoder, _headersEnumerator, buffer, out var payloadLength);
                     FinishWritingHeaders(streamId, payloadLength, done);
                 }
                 catch (HPackEncodingException hex)
@@ -201,7 +212,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2
                     _headersEnumerator.Initialize(headers);
                     _outgoingFrame.PrepareHeaders(Http2HeadersFrameFlags.END_STREAM, streamId);
                     var buffer = _headerEncodingBuffer.AsSpan();
-                    var done = HPackHeaderWriter.BeginEncodeHeaders(_headersEnumerator, buffer, out var payloadLength);
+                    var done = HPackHeaderWriter.BeginEncodeHeaders(_hpackEncoder, _headersEnumerator, buffer, out var payloadLength);
                     FinishWritingHeaders(streamId, payloadLength, done);
                 }
                 catch (HPackEncodingException hex)
@@ -230,7 +241,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2
             {
                 _outgoingFrame.PrepareContinuation(Http2ContinuationFrameFlags.NONE, streamId);
 
-                done = HPackHeaderWriter.ContinueEncodeHeaders(_headersEnumerator, buffer, out payloadLength);
+                done = HPackHeaderWriter.ContinueEncodeHeaders(_hpackEncoder, _headersEnumerator, buffer, out payloadLength);
                 _outgoingFrame.PayloadLength = payloadLength;
 
                 if (done)

src/Servers/Kestrel/Core/src/Internal/Http2/Http2HeaderEnumerator.cs

@@ -3,6 +3,7 @@
 
 using System.Collections;
 using System.Collections.Generic;
+using System.Net.Http.HPack;
 using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http;
 using Microsoft.Extensions.Primitives;
 
@@ -15,8 +16,9 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2
         private HttpResponseTrailers.Enumerator _trailersEnumerator;
         private IEnumerator<KeyValuePair<string, StringValues>> _genericEnumerator;
         private StringValues.Enumerator _stringValuesEnumerator;
+        private KnownHeaderType _knownHeaderType;
 
-        public KnownHeaderType KnownHeaderType { get; private set; }
+        public int HPackStaticTableId => GetResponseHeaderStaticTableId(_knownHeaderType);
         public KeyValuePair<string, string> Current { get; private set; }
         object IEnumerator.Current => Current;
 
@@ -33,7 +35,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2
 
             _stringValuesEnumerator = default;
             Current = default;
-            KnownHeaderType = default;
+            _knownHeaderType = default;
         }
 
         public void Initialize(HttpResponseTrailers headers)
@@ -45,7 +47,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2
 
             _stringValuesEnumerator = default;
             Current = default;
-            KnownHeaderType = default;
+            _knownHeaderType = default;
         }
 
         public void Initialize(IDictionary<string, StringValues> headers)
@@ -57,7 +59,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2
 
             _stringValuesEnumerator = default;
             Current = default;
-            KnownHeaderType = default;
+            _knownHeaderType = default;
         }
 
         public bool MoveNext()
@@ -110,7 +112,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2
                 else
                 {
                     enumerator = _genericEnumerator.Current.Value.GetEnumerator();
-                    KnownHeaderType = default;
+                    _knownHeaderType = default;
                     return true;
                 }
             }
@@ -124,7 +126,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2
                 else
                 {
                     enumerator = _trailersEnumerator.Current.Value.GetEnumerator();
-                    KnownHeaderType = _trailersEnumerator.CurrentKnownType;
+                    _knownHeaderType = _trailersEnumerator.CurrentKnownType;
                     return true;
                 }
             }
@@ -138,7 +140,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2
                 else
                 {
                     enumerator = _headersEnumerator.Current.Value.GetEnumerator();
-                    KnownHeaderType = _headersEnumerator.CurrentKnownType;
+                    _knownHeaderType = _headersEnumerator.CurrentKnownType;
                     return true;
                 }
             }
@@ -159,11 +161,68 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2
                 _headersEnumerator.Reset();
             }
             _stringValuesEnumerator = default;
-            KnownHeaderType = default;
+            _knownHeaderType = default;
         }
 
         public void Dispose()
         {
         }
+
+        internal static int GetResponseHeaderStaticTableId(KnownHeaderType responseHeaderType)
+        {
+            switch (responseHeaderType)
+            {
+                case KnownHeaderType.CacheControl:
+                    return H2StaticTable.CacheControl;
+                case KnownHeaderType.Date:
+                    return H2StaticTable.Date;
+                case KnownHeaderType.TransferEncoding:
+                    return H2StaticTable.TransferEncoding;
+                case KnownHeaderType.Via:
+                    return H2StaticTable.Via;
+                case KnownHeaderType.Allow:
+                    return H2StaticTable.Allow;
+                case KnownHeaderType.ContentType:
+                    return H2StaticTable.ContentType;
+                case KnownHeaderType.ContentEncoding:
+                    return H2StaticTable.ContentEncoding;
+                case KnownHeaderType.ContentLanguage:
+                    return H2StaticTable.ContentLanguage;
+                case KnownHeaderType.ContentLocation:
+                    return H2StaticTable.ContentLocation;
+                case KnownHeaderType.ContentRange:
+                    return H2StaticTable.ContentRange;
+                case KnownHeaderType.Expires:
+                    return H2StaticTable.Expires;
+                case KnownHeaderType.LastModified:
+                    return H2StaticTable.LastModified;
+                case KnownHeaderType.AcceptRanges:
+                    return H2StaticTable.AcceptRanges;
+                case KnownHeaderType.Age:
+                    return H2StaticTable.Age;
+                case KnownHeaderType.ETag:
+                    return H2StaticTable.ETag;
+                case KnownHeaderType.Location:
+                    return H2StaticTable.Location;
+                case KnownHeaderType.ProxyAuthenticate:
+                    return H2StaticTable.ProxyAuthenticate;
+                case KnownHeaderType.RetryAfter:
+                    return H2StaticTable.RetryAfter;
+                case KnownHeaderType.Server:
+                    return H2StaticTable.Server;
+                case KnownHeaderType.SetCookie:
+                    return H2StaticTable.SetCookie;
+                case KnownHeaderType.Vary:
+                    return H2StaticTable.Vary;
+                case KnownHeaderType.WWWAuthenticate:
+                    return H2StaticTable.WwwAuthenticate;
+                case KnownHeaderType.AccessControlAllowOrigin:
+                    return H2StaticTable.AccessControlAllowOrigin;
+                case KnownHeaderType.ContentLength:
+                    return H2StaticTable.ContentLength;
+                default:
+                    return -1;
+            }
+        }
     }
 }

src/Servers/Kestrel/Core/src/KestrelServerOptions.cs

@@ -38,6 +38,16 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core
         /// </remarks>
         public bool AddServerHeader { get; set; } = true;
 
+        /// <summary>
+        /// Gets or sets a value that controls whether dynamic compression of response headers is allowed.
+        /// For more information about the security considerations of HPack dynamic header compression, visit
+        /// https://tools.ietf.org/html/rfc7541#section-7.
+        /// </summary>
+        /// <remarks>
+        /// Defaults to true.
+        /// </remarks>
+        public bool AllowResponseHeaderCompression { get; set; } = true;
+
         /// <summary>
         /// Gets or sets a value that controls whether synchronous IO is allowed for the <see cref="HttpContext.Request"/> and <see cref="HttpContext.Response"/>
         /// </summary>

src/Servers/Kestrel/Core/src/Microsoft.AspNetCore.Server.Kestrel.Core.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <Description>Core components of ASP.NET Core Kestrel cross-platform web server.</Description>
@@ -16,9 +16,10 @@
     <Compile Include="$(SharedSourceRoot)CertificateGeneration\**\*.cs" />
     <Compile Include="$(SharedSourceRoot)ValueTaskExtensions\**\*.cs" />
     <Compile Include="$(SharedSourceRoot)UrlDecoder\**\*.cs" />
-    <Compile Include="$(SharedSourceRoot)runtime\*.cs" Link="Shared\runtime\%(Filename)%(Extension)"/>
-    <Compile Include="$(SharedSourceRoot)runtime\Http2\**\*.cs" Link="Shared\runtime\Http2\%(Filename)%(Extension)"/>
-    <Compile Include="$(SharedSourceRoot)runtime\Http3\**\*.cs" Link="Shared\runtime\Http3\%(Filename)%(Extension)"/>
+    <Compile Include="$(SharedSourceRoot)runtime\*.cs" Link="Shared\runtime\%(Filename)%(Extension)" />
+    <Compile Include="$(SharedSourceRoot)runtime\Http2\**\*.cs" Link="Shared\runtime\Http2\%(Filename)%(Extension)" />
+    <Compile Include="$(SharedSourceRoot)runtime\Http3\**\*.cs" Link="Shared\runtime\Http3\%(Filename)%(Extension)" />
+    <Compile Include="$(SharedSourceRoot)Hpack\**\*.cs" Link="Shared\Hpack\%(Filename)%(Extension)" />
     <Compile Include="$(SharedSourceRoot)ServerInfrastructure\**\*.cs" LinkBase="Shared\" />
     <Compile Include="$(RepoRoot)src\Shared\TaskToApm.cs" Link="Internal\TaskToApm.cs" />
   </ItemGroup>

src/Servers/Kestrel/Core/test/HPackHeaderWriterTests.cs

@@ -1,199 +1,199 @@
-// Copyright (c) .NET Foundation. All rights reserved.
-// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+//// Copyright (c) .NET Foundation. All rights reserved.
+//// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2;
-using Microsoft.Extensions.Primitives;
-using Xunit;
+//using System;
+//using System.Collections.Generic;
+//using System.Linq;
+//using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2;
+//using Microsoft.Extensions.Primitives;
+//using Xunit;
 
-namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
-{
-    public class HPackHeaderWriterTests
-    {
-        public static TheoryData<KeyValuePair<string, string>[], byte[], int?> SinglePayloadData
-        {
-            get
-            {
-                var data = new TheoryData<KeyValuePair<string, string>[], byte[], int?>();
+//namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
+//{
+//    public class HPackHeaderWriterTests
+//    {
+//        public static TheoryData<KeyValuePair<string, string>[], byte[], int?> SinglePayloadData
+//        {
+//            get
+//            {
+//                var data = new TheoryData<KeyValuePair<string, string>[], byte[], int?>();
 
-                // Lowercase header name letters only
-                data.Add(
-                    new[]
-                    {
-                        new KeyValuePair<string, string>("CustomHeader", "CustomValue"),
-                    },
-                    new byte[]
-                    {
-                        // 0    12     c     u     s     t     o     m
-                        0x00, 0x0c, 0x63, 0x75, 0x73, 0x74, 0x6f, 0x6d,
-                        // h     e     a     d     e     r    11     C
-                        0x68, 0x65, 0x61, 0x64, 0x65, 0x72, 0x0b, 0x43,
-                        // u     s     t     o     m     V     a     l
-                        0x75, 0x73, 0x74, 0x6f, 0x6d, 0x56, 0x61, 0x6c,
-                        // u     e
-                        0x75, 0x65
-                    },
-                    null);
-                // Lowercase header name letters only
-                data.Add(
-                    new[]
-                    {
-                        new KeyValuePair<string, string>("CustomHeader!#$%&'*+-.^_`|~", "CustomValue"),
-                    },
-                    new byte[]
-                    {
-                        // 0    27     c     u     s     t     o     m
-                        0x00, 0x1b, 0x63, 0x75, 0x73, 0x74, 0x6f, 0x6d,
-                        // h     e     a     d     e     r     !     #
-                        0x68, 0x65, 0x61, 0x64, 0x65, 0x72, 0x21, 0x23,
-                        // $     %     &     '     *     +     -     .
-                        0x24, 0x25, 0x26, 0x27, 0x2a, 0x2b, 0x2d, 0x2e,
-                        // ^     _     `     |     ~    11     C     u
-                        0x5e, 0x5f, 0x60, 0x7c, 0x7e, 0x0b, 0x43, 0x75,
-                        // s     t     o     m     V     a     l     u
-                        0x73, 0x74, 0x6f, 0x6d, 0x56, 0x61, 0x6c, 0x75,
-                        // e
-                        0x65
-                    },
-                    null);
-                // Single Payload
-                data.Add(
-                    new[]
-                    {
-                        new KeyValuePair<string, string>("date", "Mon, 24 Jul 2017 19:22:30 GMT"),
-                        new KeyValuePair<string, string>("content-type", "text/html; charset=utf-8"),
-                        new KeyValuePair<string, string>("server", "Kestrel")
-                    },
-                    new byte[]
-                    {
-                        0x88, 0x00, 0x04, 0x64, 0x61, 0x74, 0x65, 0x1d,
-                        0x4d, 0x6f, 0x6e, 0x2c, 0x20, 0x32, 0x34, 0x20,
-                        0x4a, 0x75, 0x6c, 0x20, 0x32, 0x30, 0x31, 0x37,
-                        0x20, 0x31, 0x39, 0x3a, 0x32, 0x32, 0x3a, 0x33,
-                        0x30, 0x20, 0x47, 0x4d, 0x54, 0x00, 0x0c, 0x63,
-                        0x6f, 0x6e, 0x74, 0x65, 0x6e, 0x74, 0x2d, 0x74,
-                        0x79, 0x70, 0x65, 0x18, 0x74, 0x65, 0x78, 0x74,
-                        0x2f, 0x68, 0x74, 0x6d, 0x6c, 0x3b, 0x20, 0x63,
-                        0x68, 0x61, 0x72, 0x73, 0x65, 0x74, 0x3d, 0x75,
-                        0x74, 0x66, 0x2d, 0x38, 0x00, 0x06, 0x73, 0x65,
-                        0x72, 0x76, 0x65, 0x72, 0x07, 0x4b, 0x65, 0x73,
-                        0x74, 0x72, 0x65, 0x6c
-                    },
-                    200);
+//                // Lowercase header name letters only
+//                data.Add(
+//                    new[]
+//                    {
+//                        new KeyValuePair<string, string>("CustomHeader", "CustomValue"),
+//                    },
+//                    new byte[]
+//                    {
+//                        // 0    12     c     u     s     t     o     m
+//                        0x00, 0x0c, 0x63, 0x75, 0x73, 0x74, 0x6f, 0x6d,
+//                        // h     e     a     d     e     r    11     C
+//                        0x68, 0x65, 0x61, 0x64, 0x65, 0x72, 0x0b, 0x43,
+//                        // u     s     t     o     m     V     a     l
+//                        0x75, 0x73, 0x74, 0x6f, 0x6d, 0x56, 0x61, 0x6c,
+//                        // u     e
+//                        0x75, 0x65
+//                    },
+//                    null);
+//                // Lowercase header name letters only
+//                data.Add(
+//                    new[]
+//                    {
+//                        new KeyValuePair<string, string>("CustomHeader!#$%&'*+-.^_`|~", "CustomValue"),
+//                    },
+//                    new byte[]
+//                    {
+//                        // 0    27     c     u     s     t     o     m
+//                        0x00, 0x1b, 0x63, 0x75, 0x73, 0x74, 0x6f, 0x6d,
+//                        // h     e     a     d     e     r     !     #
+//                        0x68, 0x65, 0x61, 0x64, 0x65, 0x72, 0x21, 0x23,
+//                        // $     %     &     '     *     +     -     .
+//                        0x24, 0x25, 0x26, 0x27, 0x2a, 0x2b, 0x2d, 0x2e,
+//                        // ^     _     `     |     ~    11     C     u
+//                        0x5e, 0x5f, 0x60, 0x7c, 0x7e, 0x0b, 0x43, 0x75,
+//                        // s     t     o     m     V     a     l     u
+//                        0x73, 0x74, 0x6f, 0x6d, 0x56, 0x61, 0x6c, 0x75,
+//                        // e
+//                        0x65
+//                    },
+//                    null);
+//                // Single Payload
+//                data.Add(
+//                    new[]
+//                    {
+//                        new KeyValuePair<string, string>("date", "Mon, 24 Jul 2017 19:22:30 GMT"),
+//                        new KeyValuePair<string, string>("content-type", "text/html; charset=utf-8"),
+//                        new KeyValuePair<string, string>("server", "Kestrel")
+//                    },
+//                    new byte[]
+//                    {
+//                        0x88, 0x00, 0x04, 0x64, 0x61, 0x74, 0x65, 0x1d,
+//                        0x4d, 0x6f, 0x6e, 0x2c, 0x20, 0x32, 0x34, 0x20,
+//                        0x4a, 0x75, 0x6c, 0x20, 0x32, 0x30, 0x31, 0x37,
+//                        0x20, 0x31, 0x39, 0x3a, 0x32, 0x32, 0x3a, 0x33,
+//                        0x30, 0x20, 0x47, 0x4d, 0x54, 0x00, 0x0c, 0x63,
+//                        0x6f, 0x6e, 0x74, 0x65, 0x6e, 0x74, 0x2d, 0x74,
+//                        0x79, 0x70, 0x65, 0x18, 0x74, 0x65, 0x78, 0x74,
+//                        0x2f, 0x68, 0x74, 0x6d, 0x6c, 0x3b, 0x20, 0x63,
+//                        0x68, 0x61, 0x72, 0x73, 0x65, 0x74, 0x3d, 0x75,
+//                        0x74, 0x66, 0x2d, 0x38, 0x00, 0x06, 0x73, 0x65,
+//                        0x72, 0x76, 0x65, 0x72, 0x07, 0x4b, 0x65, 0x73,
+//                        0x74, 0x72, 0x65, 0x6c
+//                    },
+//                    200);
 
-                return data;
-            }
-        }
+//                return data;
+//            }
+//        }
 
-        [Theory]
-        [MemberData(nameof(SinglePayloadData))]
-        public void EncodesHeadersInSinglePayloadWhenSpaceAvailable(KeyValuePair<string, string>[] headers, byte[] expectedPayload, int? statusCode)
-        {
-            var payload = new byte[1024];
-            var length = 0;
-            if (statusCode.HasValue)
-            {
-                Assert.True(HPackHeaderWriter.BeginEncodeHeaders(statusCode.Value, GetHeadersEnumerator(headers), payload, out length));
-            }
-            else
-            {
-                Assert.True(HPackHeaderWriter.BeginEncodeHeaders(GetHeadersEnumerator(headers), payload, out length));
-            }
-            Assert.Equal(expectedPayload.Length, length);
+//        [Theory]
+//        [MemberData(nameof(SinglePayloadData))]
+//        public void EncodesHeadersInSinglePayloadWhenSpaceAvailable(KeyValuePair<string, string>[] headers, byte[] expectedPayload, int? statusCode)
+//        {
+//            var payload = new byte[1024];
+//            var length = 0;
+//            if (statusCode.HasValue)
+//            {
+//                Assert.True(HPackHeaderWriter.BeginEncodeHeaders(statusCode.Value, GetHeadersEnumerator(headers), payload, out length));
+//            }
+//            else
+//            {
+//                Assert.True(HPackHeaderWriter.BeginEncodeHeaders(GetHeadersEnumerator(headers), payload, out length));
+//            }
+//            Assert.Equal(expectedPayload.Length, length);
 
-            for (var i = 0; i < length; i++)
-            {
-                Assert.True(expectedPayload[i] == payload[i], $"{expectedPayload[i]} != {payload[i]} at {i} (len {length})");
-            }
+//            for (var i = 0; i < length; i++)
+//            {
+//                Assert.True(expectedPayload[i] == payload[i], $"{expectedPayload[i]} != {payload[i]} at {i} (len {length})");
+//            }
 
-            Assert.Equal(expectedPayload, new ArraySegment<byte>(payload, 0, length));
-        }
+//            Assert.Equal(expectedPayload, new ArraySegment<byte>(payload, 0, length));
+//        }
 
-        [Theory]
-        [InlineData(true)]
-        [InlineData(false)]
-        public void EncodesHeadersInMultiplePayloadsWhenSpaceNotAvailable(bool exactSize)
-        {
-            var statusCode = 200;
-            var headers = new[]
-            {
-                new KeyValuePair<string, string>("date", "Mon, 24 Jul 2017 19:22:30 GMT"),
-                new KeyValuePair<string, string>("content-type", "text/html; charset=utf-8"),
-                new KeyValuePair<string, string>("server", "Kestrel")
-            };
+//        [Theory]
+//        [InlineData(true)]
+//        [InlineData(false)]
+//        public void EncodesHeadersInMultiplePayloadsWhenSpaceNotAvailable(bool exactSize)
+//        {
+//            var statusCode = 200;
+//            var headers = new[]
+//            {
+//                new KeyValuePair<string, string>("date", "Mon, 24 Jul 2017 19:22:30 GMT"),
+//                new KeyValuePair<string, string>("content-type", "text/html; charset=utf-8"),
+//                new KeyValuePair<string, string>("server", "Kestrel")
+//            };
 
-            var expectedStatusCodePayload = new byte[]
-            {
-                0x88
-            };
+//            var expectedStatusCodePayload = new byte[]
+//            {
+//                0x88
+//            };
 
-            var expectedDateHeaderPayload = new byte[]
-            {
-                0x00, 0x04, 0x64, 0x61, 0x74, 0x65, 0x1d, 0x4d,
-                0x6f, 0x6e, 0x2c, 0x20, 0x32, 0x34, 0x20, 0x4a,
-                0x75, 0x6c, 0x20, 0x32, 0x30, 0x31, 0x37, 0x20,
-                0x31, 0x39, 0x3a, 0x32, 0x32, 0x3a, 0x33, 0x30,
-                0x20, 0x47, 0x4d, 0x54
-            };
+//            var expectedDateHeaderPayload = new byte[]
+//            {
+//                0x00, 0x04, 0x64, 0x61, 0x74, 0x65, 0x1d, 0x4d,
+//                0x6f, 0x6e, 0x2c, 0x20, 0x32, 0x34, 0x20, 0x4a,
+//                0x75, 0x6c, 0x20, 0x32, 0x30, 0x31, 0x37, 0x20,
+//                0x31, 0x39, 0x3a, 0x32, 0x32, 0x3a, 0x33, 0x30,
+//                0x20, 0x47, 0x4d, 0x54
+//            };
 
-            var expectedContentTypeHeaderPayload = new byte[]
-            {
-                0x00, 0x0c, 0x63, 0x6f, 0x6e, 0x74, 0x65, 0x6e,
-                0x74, 0x2d, 0x74, 0x79, 0x70, 0x65, 0x18, 0x74,
-                0x65, 0x78, 0x74, 0x2f, 0x68, 0x74, 0x6d, 0x6c,
-                0x3b, 0x20, 0x63, 0x68, 0x61, 0x72, 0x73, 0x65,
-                0x74, 0x3d, 0x75, 0x74, 0x66, 0x2d, 0x38
-            };
+//            var expectedContentTypeHeaderPayload = new byte[]
+//            {
+//                0x00, 0x0c, 0x63, 0x6f, 0x6e, 0x74, 0x65, 0x6e,
+//                0x74, 0x2d, 0x74, 0x79, 0x70, 0x65, 0x18, 0x74,
+//                0x65, 0x78, 0x74, 0x2f, 0x68, 0x74, 0x6d, 0x6c,
+//                0x3b, 0x20, 0x63, 0x68, 0x61, 0x72, 0x73, 0x65,
+//                0x74, 0x3d, 0x75, 0x74, 0x66, 0x2d, 0x38
+//            };
 
-            var expectedServerHeaderPayload = new byte[]
-            {
-                0x00, 0x06, 0x73, 0x65, 0x72, 0x76, 0x65, 0x72,
-                0x07, 0x4b, 0x65, 0x73, 0x74, 0x72, 0x65, 0x6c
-            };
+//            var expectedServerHeaderPayload = new byte[]
+//            {
+//                0x00, 0x06, 0x73, 0x65, 0x72, 0x76, 0x65, 0x72,
+//                0x07, 0x4b, 0x65, 0x73, 0x74, 0x72, 0x65, 0x6c
+//            };
 
-            Span<byte> payload = new byte[1024];
-            var offset = 0;
-            var headerEnumerator = GetHeadersEnumerator(headers);
+//            Span<byte> payload = new byte[1024];
+//            var offset = 0;
+//            var headerEnumerator = GetHeadersEnumerator(headers);
 
-            // When !exactSize, slices are one byte short of fitting the next header
-            var sliceLength = expectedStatusCodePayload.Length + (exactSize ? 0 : expectedDateHeaderPayload.Length - 1);
-            Assert.False(HPackHeaderWriter.BeginEncodeHeaders(statusCode, headerEnumerator, payload.Slice(offset, sliceLength), out var length));
-            Assert.Equal(expectedStatusCodePayload.Length, length);
-            Assert.Equal(expectedStatusCodePayload, payload.Slice(0, length).ToArray());
+//            // When !exactSize, slices are one byte short of fitting the next header
+//            var sliceLength = expectedStatusCodePayload.Length + (exactSize ? 0 : expectedDateHeaderPayload.Length - 1);
+//            Assert.False(HPackHeaderWriter.BeginEncodeHeaders(statusCode, headerEnumerator, payload.Slice(offset, sliceLength), out var length));
+//            Assert.Equal(expectedStatusCodePayload.Length, length);
+//            Assert.Equal(expectedStatusCodePayload, payload.Slice(0, length).ToArray());
 
-            offset += length;
+//            offset += length;
 
-            sliceLength = expectedDateHeaderPayload.Length + (exactSize ? 0 : expectedContentTypeHeaderPayload.Length - 1);
-            Assert.False(HPackHeaderWriter.ContinueEncodeHeaders(headerEnumerator, payload.Slice(offset, sliceLength), out length));
-            Assert.Equal(expectedDateHeaderPayload.Length, length);
-            Assert.Equal(expectedDateHeaderPayload, payload.Slice(offset, length).ToArray());
+//            sliceLength = expectedDateHeaderPayload.Length + (exactSize ? 0 : expectedContentTypeHeaderPayload.Length - 1);
+//            Assert.False(HPackHeaderWriter.ContinueEncodeHeaders(headerEnumerator, payload.Slice(offset, sliceLength), out length));
+//            Assert.Equal(expectedDateHeaderPayload.Length, length);
+//            Assert.Equal(expectedDateHeaderPayload, payload.Slice(offset, length).ToArray());
 
-            offset += length;
+//            offset += length;
 
-            sliceLength = expectedContentTypeHeaderPayload.Length + (exactSize ? 0 : expectedServerHeaderPayload.Length - 1);
-            Assert.False(HPackHeaderWriter.ContinueEncodeHeaders(headerEnumerator, payload.Slice(offset, sliceLength), out length));
-            Assert.Equal(expectedContentTypeHeaderPayload.Length, length);
-            Assert.Equal(expectedContentTypeHeaderPayload, payload.Slice(offset, length).ToArray());
+//            sliceLength = expectedContentTypeHeaderPayload.Length + (exactSize ? 0 : expectedServerHeaderPayload.Length - 1);
+//            Assert.False(HPackHeaderWriter.ContinueEncodeHeaders(headerEnumerator, payload.Slice(offset, sliceLength), out length));
+//            Assert.Equal(expectedContentTypeHeaderPayload.Length, length);
+//            Assert.Equal(expectedContentTypeHeaderPayload, payload.Slice(offset, length).ToArray());
 
-            offset += length;
+//            offset += length;
 
-            sliceLength = expectedServerHeaderPayload.Length;
-            Assert.True(HPackHeaderWriter.ContinueEncodeHeaders(headerEnumerator, payload.Slice(offset, sliceLength), out length));
-            Assert.Equal(expectedServerHeaderPayload.Length, length);
-            Assert.Equal(expectedServerHeaderPayload, payload.Slice(offset, length).ToArray());
-        }
+//            sliceLength = expectedServerHeaderPayload.Length;
+//            Assert.True(HPackHeaderWriter.ContinueEncodeHeaders(headerEnumerator, payload.Slice(offset, sliceLength), out length));
+//            Assert.Equal(expectedServerHeaderPayload.Length, length);
+//            Assert.Equal(expectedServerHeaderPayload, payload.Slice(offset, length).ToArray());
+//        }
 
-        private static Http2HeadersEnumerator GetHeadersEnumerator(IEnumerable<KeyValuePair<string, string>> headers)
-        {
-            var groupedHeaders = headers
-                .GroupBy(k => k.Key)
-                .ToDictionary(g => g.Key, g => new StringValues(g.Select(gg => gg.Value).ToArray()));
+//        private static Http2HeadersEnumerator GetHeadersEnumerator(IEnumerable<KeyValuePair<string, string>> headers)
+//        {
+//            var groupedHeaders = headers
+//                .GroupBy(k => k.Key)
+//                .ToDictionary(g => g.Key, g => new StringValues(g.Select(gg => gg.Value).ToArray()));
 
-            var enumerator = new Http2HeadersEnumerator();
-            enumerator.Initialize(groupedHeaders);
-            return enumerator;
-        }
-    }
-}
+//            var enumerator = new Http2HeadersEnumerator();
+//            enumerator.Initialize(groupedHeaders);
+//            return enumerator;
+//        }
+//    }
+//}

src/Servers/Kestrel/Core/test/Http2FrameWriterTests.cs

@@ -41,7 +41,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
         {
             // Arrange
             var pipe = new Pipe(new PipeOptions(_dirtyMemoryPool, PipeScheduler.Inline, PipeScheduler.Inline));
-            var frameWriter = new Http2FrameWriter(pipe.Writer, null, null, null, null, null, null, _dirtyMemoryPool, new Mock<IKestrelTrace>().Object);
+            var frameWriter = CreateFrameWriter(pipe);
 
             // Act
             await frameWriter.WriteWindowUpdateAsync(1, 1);
@@ -52,12 +52,22 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             Assert.Equal(new byte[] { 0x00, 0x00, 0x00, 0x01 }, payload.Skip(Http2FrameReader.HeaderLength).Take(4).ToArray());
         }
 
+        private Http2FrameWriter CreateFrameWriter(Pipe pipe)
+        {
+            var serviceContext = new Internal.ServiceContext
+            {
+                ServerOptions = new KestrelServerOptions(),
+                Log = new Mock<IKestrelTrace>().Object
+            };
+            return new Http2FrameWriter(pipe.Writer, null, null, null, null, null, null, _dirtyMemoryPool, serviceContext);
+        }
+
         [Fact]
         public async Task WriteGoAway_UnsetsReservedBit()
         {
             // Arrange
             var pipe = new Pipe(new PipeOptions(_dirtyMemoryPool, PipeScheduler.Inline, PipeScheduler.Inline));
-            var frameWriter = new Http2FrameWriter(pipe.Writer, null, null, null, null, null, null, _dirtyMemoryPool, new Mock<IKestrelTrace>().Object);
+            var frameWriter = CreateFrameWriter(pipe);
 
             // Act
             await frameWriter.WriteGoAwayAsync(1, Http2ErrorCode.NO_ERROR);

src/Servers/Kestrel/Core/test/Http2HPackEncoderTests.cs

@@ -0,0 +1,479 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Net.Http.HPack;
+using System.Text;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http;
+using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2;
+using Microsoft.Extensions.Primitives;
+using Xunit;
+
+namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
+{
+    public class Http2HPackEncoderTests
+    {
+        [Fact]
+        public void BeginEncodeHeaders_Status302_NewIndexValue()
+        {
+            Span<byte> buffer = new byte[1024 * 16];
+
+            var headers = new HttpResponseHeaders();
+            var enumerator = new Http2HeadersEnumerator();
+            enumerator.Initialize(headers);
+
+            var hpackEncoder = new HPackEncoder();
+            Assert.True(HPackHeaderWriter.BeginEncodeHeaders(302, hpackEncoder, enumerator, buffer, out var length));
+
+            var result = buffer.Slice(0, length).ToArray();
+            var hex = BitConverter.ToString(result);
+            Assert.Equal("48-03-33-30-32", hex);
+
+            var statusHeader = GetHeaderEntry(hpackEncoder, 0);
+            Assert.Equal(":status", statusHeader.Name);
+            Assert.Equal("302", statusHeader.Value);
+        }
+
+        [Fact]
+        public void BeginEncodeHeaders_CacheControlPrivate_NewIndexValue()
+        {
+            Span<byte> buffer = new byte[1024 * 16];
+
+            var headers = new HttpResponseHeaders();
+            headers.HeaderCacheControl = "private";
+
+            var enumerator = new Http2HeadersEnumerator();
+            enumerator.Initialize(headers);
+
+            var hpackEncoder = new HPackEncoder();
+            Assert.True(HPackHeaderWriter.BeginEncodeHeaders(302, hpackEncoder, enumerator, buffer, out var length));
+
+            var result = buffer.Slice(5, length - 5).ToArray();
+            var hex = BitConverter.ToString(result);
+            Assert.Equal("58-07-70-72-69-76-61-74-65", hex);
+
+            var statusHeader = GetHeaderEntry(hpackEncoder, 0);
+            Assert.Equal("Cache-Control", statusHeader.Name);
+            Assert.Equal("private", statusHeader.Value);
+        }
+
+        [Fact]
+        public void BeginEncodeHeaders_MaxHeaderTableSizeExceeded_EvictionsToFit()
+        {
+            // Test follows example https://tools.ietf.org/html/rfc7541#appendix-C.5
+
+            Span<byte> buffer = new byte[1024 * 16];
+
+            var headers = new HttpResponseHeaders();
+            headers.HeaderCacheControl = "private";
+            headers.HeaderDate = "Mon, 21 Oct 2013 20:13:21 GMT";
+            headers.HeaderLocation = "https://www.example.com";
+
+            var enumerator = new Http2HeadersEnumerator();
+
+            var hpackEncoder = new HPackEncoder(maxHeaderTableSize: 256);
+
+            // First response
+            enumerator.Initialize(headers);
+            Assert.True(HPackHeaderWriter.BeginEncodeHeaders(302, hpackEncoder, enumerator, buffer, out var length));
+
+            var result = buffer.Slice(0, length).ToArray();
+            var hex = BitConverter.ToString(result);
+            Assert.Equal(
+                "48-03-33-30-32-58-07-70-72-69-76-61-74-65-61-1D-" +
+                "4D-6F-6E-2C-20-32-31-20-4F-63-74-20-32-30-31-33-" +
+                "20-32-30-3A-31-33-3A-32-31-20-47-4D-54-6E-17-68-" +
+                "74-74-70-73-3A-2F-2F-77-77-77-2E-65-78-61-6D-70-" +
+                "6C-65-2E-63-6F-6D", hex);
+
+            var entries = GetHeaderEntries(hpackEncoder);
+            Assert.Collection(entries,
+                e =>
+                {
+                    Assert.Equal("Location", e.Name);
+                    Assert.Equal("https://www.example.com", e.Value);
+                },
+                e =>
+                {
+                    Assert.Equal("Date", e.Name);
+                    Assert.Equal("Mon, 21 Oct 2013 20:13:21 GMT", e.Value);
+                },
+                e =>
+                {
+                    Assert.Equal("Cache-Control", e.Name);
+                    Assert.Equal("private", e.Value);
+                },
+                e =>
+                {
+                    Assert.Equal(":status", e.Name);
+                    Assert.Equal("302", e.Value);
+                });
+
+            // Second response
+            enumerator.Initialize(headers);
+            Assert.True(HPackHeaderWriter.BeginEncodeHeaders(307, hpackEncoder, enumerator, buffer, out length));
+
+            result = buffer.Slice(0, length).ToArray();
+            hex = BitConverter.ToString(result);
+            Assert.Equal("48-03-33-30-37-C1-C0-BF", hex);
+
+            entries = GetHeaderEntries(hpackEncoder);
+            Assert.Collection(entries,
+                e =>
+                {
+                    Assert.Equal(":status", e.Name);
+                    Assert.Equal("307", e.Value);
+                },
+                e =>
+                {
+                    Assert.Equal("Location", e.Name);
+                    Assert.Equal("https://www.example.com", e.Value);
+                },
+                e =>
+                {
+                    Assert.Equal("Date", e.Name);
+                    Assert.Equal("Mon, 21 Oct 2013 20:13:21 GMT", e.Value);
+                },
+                e =>
+                {
+                    Assert.Equal("Cache-Control", e.Name);
+                    Assert.Equal("private", e.Value);
+                });
+
+            // Third response
+            headers.HeaderDate = "Mon, 21 Oct 2013 20:13:22 GMT";
+            headers.HeaderContentEncoding = "gzip";
+            headers.HeaderSetCookie = "foo=ASDJKHQKBZXOQWEOPIUAXQWEOIU; max-age=3600; version=1";
+
+            enumerator.Initialize(headers);
+            Assert.True(HPackHeaderWriter.BeginEncodeHeaders(200, hpackEncoder, enumerator, buffer, out length));
+
+            result = buffer.Slice(0, length).ToArray();
+            hex = BitConverter.ToString(result);
+            Assert.Equal(
+                "88-C1-61-1D-4D-6F-6E-2C-20-32-31-20-4F-63-74-20-" +
+                "32-30-31-33-20-32-30-3A-31-33-3A-32-32-20-47-4D-" +
+                "54-5A-04-67-7A-69-70-C1-1F-28-38-66-6F-6F-3D-41-" +
+                "53-44-4A-4B-48-51-4B-42-5A-58-4F-51-57-45-4F-50-" +
+                "49-55-41-58-51-57-45-4F-49-55-3B-20-6D-61-78-2D-" +
+                "61-67-65-3D-33-36-30-30-3B-20-76-65-72-73-69-6F-" +
+                "6E-3D-31", hex);
+
+            entries = GetHeaderEntries(hpackEncoder);
+            Assert.Collection(entries,
+                e =>
+                {
+                    Assert.Equal("Content-Encoding", e.Name);
+                    Assert.Equal("gzip", e.Value);
+                },
+                e =>
+                {
+                    Assert.Equal("Date", e.Name);
+                    Assert.Equal("Mon, 21 Oct 2013 20:13:22 GMT", e.Value);
+                },
+                e =>
+                {
+                    Assert.Equal(":status", e.Name);
+                    Assert.Equal("307", e.Value);
+                },
+                e =>
+                {
+                    Assert.Equal("Location", e.Name);
+                    Assert.Equal("https://www.example.com", e.Value);
+                });
+        }
+
+        [Theory]
+        [InlineData("Set-Cookie", true)]
+        [InlineData("Content-Disposition", true)]
+        [InlineData("Content-Length", false)]
+        public void BeginEncodeHeaders_ExcludedHeaders_NotAddedToTable(string headerName, bool neverIndex)
+        {
+            Span<byte> buffer = new byte[1024 * 16];
+
+            var headers = new HttpResponseHeaders();
+            headers.Append(headerName, "1");
+
+            var enumerator = new Http2HeadersEnumerator();
+            enumerator.Initialize(headers);
+
+            var hpackEncoder = new HPackEncoder(maxHeaderTableSize: Http2PeerSettings.DefaultHeaderTableSize);
+            Assert.True(HPackHeaderWriter.BeginEncodeHeaders(hpackEncoder, enumerator, buffer, out _));
+
+            if (neverIndex)
+            {
+                Assert.Equal(0x10, buffer[0] & 0x10);
+            }
+            else
+            {
+                Assert.Equal(0, buffer[0] & 0x40);
+            }
+
+            Assert.Empty(GetHeaderEntries(hpackEncoder));
+        }
+
+        [Fact]
+        public void BeginEncodeHeaders_HeaderExceedHeaderTableSize_NoIndexAndNoHeaderEntry()
+        {
+            Span<byte> buffer = new byte[1024 * 16];
+
+            var headers = new HttpResponseHeaders();
+            headers.Append("x-Custom", new string('!', (int)Http2PeerSettings.DefaultHeaderTableSize));
+
+            var enumerator = new Http2HeadersEnumerator();
+            enumerator.Initialize(headers);
+
+            var hpackEncoder = new HPackEncoder();
+            Assert.True(HPackHeaderWriter.BeginEncodeHeaders(200, hpackEncoder, enumerator, buffer, out var length));
+
+            Assert.Empty(GetHeaderEntries(hpackEncoder));
+        }
+
+        public static TheoryData<KeyValuePair<string, string>[], byte[], int?> SinglePayloadData
+        {
+            get
+            {
+                var data = new TheoryData<KeyValuePair<string, string>[], byte[], int?>();
+
+                // Lowercase header name letters only
+                data.Add(
+                    new[]
+                    {
+                        new KeyValuePair<string, string>("CustomHeader", "CustomValue"),
+                    },
+                    new byte[]
+                    {
+                        //      12     c     u     s     t     o     m
+                        0x40, 0x0c, 0x63, 0x75, 0x73, 0x74, 0x6f, 0x6d,
+                        // h     e     a     d     e     r    11     C
+                        0x68, 0x65, 0x61, 0x64, 0x65, 0x72, 0x0b, 0x43,
+                        // u     s     t     o     m     V     a     l
+                        0x75, 0x73, 0x74, 0x6f, 0x6d, 0x56, 0x61, 0x6c,
+                        // u     e
+                        0x75, 0x65
+                    },
+                    null);
+                // Lowercase header name letters only
+                data.Add(
+                    new[]
+                    {
+                        new KeyValuePair<string, string>("CustomHeader!#$%&'*+-.^_`|~", "CustomValue"),
+                    },
+                    new byte[]
+                    {
+                        //      27     c     u     s     t     o     m
+                        0x40, 0x1b, 0x63, 0x75, 0x73, 0x74, 0x6f, 0x6d,
+                        // h     e     a     d     e     r     !     #
+                        0x68, 0x65, 0x61, 0x64, 0x65, 0x72, 0x21, 0x23,
+                        // $     %     &     '     *     +     -     .
+                        0x24, 0x25, 0x26, 0x27, 0x2a, 0x2b, 0x2d, 0x2e,
+                        // ^     _     `     |     ~    11     C     u
+                        0x5e, 0x5f, 0x60, 0x7c, 0x7e, 0x0b, 0x43, 0x75,
+                        // s     t     o     m     V     a     l     u
+                        0x73, 0x74, 0x6f, 0x6d, 0x56, 0x61, 0x6c, 0x75,
+                        // e
+                        0x65
+                    },
+                    null);
+                // Single Payload
+                data.Add(
+                    new[]
+                    {
+                        new KeyValuePair<string, string>("date", "Mon, 24 Jul 2017 19:22:30 GMT"),
+                        new KeyValuePair<string, string>("content-type", "text/html; charset=utf-8"),
+                        new KeyValuePair<string, string>("server", "Kestrel")
+                    },
+                    new byte[]
+                    {
+                        0x88, 0x40, 0x04, 0x64, 0x61, 0x74, 0x65, 0x1d,
+                        0x4d, 0x6f, 0x6e, 0x2c, 0x20, 0x32, 0x34, 0x20,
+                        0x4a, 0x75, 0x6c, 0x20, 0x32, 0x30, 0x31, 0x37,
+                        0x20, 0x31, 0x39, 0x3a, 0x32, 0x32, 0x3a, 0x33,
+                        0x30, 0x20, 0x47, 0x4d, 0x54, 0x40, 0x0c, 0x63,
+                        0x6f, 0x6e, 0x74, 0x65, 0x6e, 0x74, 0x2d, 0x74,
+                        0x79, 0x70, 0x65, 0x18, 0x74, 0x65, 0x78, 0x74,
+                        0x2f, 0x68, 0x74, 0x6d, 0x6c, 0x3b, 0x20, 0x63,
+                        0x68, 0x61, 0x72, 0x73, 0x65, 0x74, 0x3d, 0x75,
+                        0x74, 0x66, 0x2d, 0x38, 0x40, 0x06, 0x73, 0x65,
+                        0x72, 0x76, 0x65, 0x72, 0x07, 0x4b, 0x65, 0x73,
+                        0x74, 0x72, 0x65, 0x6c
+                    },
+                    200);
+
+                return data;
+            }
+        }
+
+        [Theory]
+        [MemberData(nameof(SinglePayloadData))]
+        public void EncodesHeadersInSinglePayloadWhenSpaceAvailable(KeyValuePair<string, string>[] headers, byte[] expectedPayload, int? statusCode)
+        {
+            HPackEncoder hpackEncoder = new HPackEncoder();
+
+            var payload = new byte[1024];
+            var length = 0;
+            if (statusCode.HasValue)
+            {
+                Assert.True(HPackHeaderWriter.BeginEncodeHeaders(statusCode.Value, hpackEncoder, GetHeadersEnumerator(headers), payload, out length));
+            }
+            else
+            {
+                Assert.True(HPackHeaderWriter.BeginEncodeHeaders(hpackEncoder, GetHeadersEnumerator(headers), payload, out length));
+            }
+            Assert.Equal(expectedPayload.Length, length);
+
+            for (var i = 0; i < length; i++)
+            {
+                Assert.True(expectedPayload[i] == payload[i], $"{expectedPayload[i]} != {payload[i]} at {i} (len {length})");
+            }
+
+            Assert.Equal(expectedPayload, new ArraySegment<byte>(payload, 0, length));
+        }
+
+        [Theory]
+        [InlineData(true)]
+        [InlineData(false)]
+        public void EncodesHeadersInMultiplePayloadsWhenSpaceNotAvailable(bool exactSize)
+        {
+            var statusCode = 200;
+            var headers = new[]
+            {
+                new KeyValuePair<string, string>("date", "Mon, 24 Jul 2017 19:22:30 GMT"),
+                new KeyValuePair<string, string>("content-type", "text/html; charset=utf-8"),
+                new KeyValuePair<string, string>("server", "Kestrel")
+            };
+
+            var expectedStatusCodePayload = new byte[]
+            {
+                0x88
+            };
+
+            var expectedDateHeaderPayload = new byte[]
+            {
+                0x40, 0x04, 0x64, 0x61, 0x74, 0x65, 0x1d, 0x4d,
+                0x6f, 0x6e, 0x2c, 0x20, 0x32, 0x34, 0x20, 0x4a,
+                0x75, 0x6c, 0x20, 0x32, 0x30, 0x31, 0x37, 0x20,
+                0x31, 0x39, 0x3a, 0x32, 0x32, 0x3a, 0x33, 0x30,
+                0x20, 0x47, 0x4d, 0x54
+            };
+
+            var expectedContentTypeHeaderPayload = new byte[]
+            {
+                0x40, 0x0c, 0x63, 0x6f, 0x6e, 0x74, 0x65, 0x6e,
+                0x74, 0x2d, 0x74, 0x79, 0x70, 0x65, 0x18, 0x74,
+                0x65, 0x78, 0x74, 0x2f, 0x68, 0x74, 0x6d, 0x6c,
+                0x3b, 0x20, 0x63, 0x68, 0x61, 0x72, 0x73, 0x65,
+                0x74, 0x3d, 0x75, 0x74, 0x66, 0x2d, 0x38
+            };
+
+            var expectedServerHeaderPayload = new byte[]
+            {
+                0x40, 0x06, 0x73, 0x65, 0x72, 0x76, 0x65, 0x72,
+                0x07, 0x4b, 0x65, 0x73, 0x74, 0x72, 0x65, 0x6c
+            };
+
+            var hpackEncoder = new HPackEncoder();
+
+            Span<byte> payload = new byte[1024];
+            var offset = 0;
+            var headerEnumerator = GetHeadersEnumerator(headers);
+
+            // When !exactSize, slices are one byte short of fitting the next header
+            var sliceLength = expectedStatusCodePayload.Length + (exactSize ? 0 : expectedDateHeaderPayload.Length - 1);
+            Assert.False(HPackHeaderWriter.BeginEncodeHeaders(statusCode, hpackEncoder, headerEnumerator, payload.Slice(offset, sliceLength), out var length));
+            Assert.Equal(expectedStatusCodePayload.Length, length);
+            Assert.Equal(expectedStatusCodePayload, payload.Slice(0, length).ToArray());
+
+            offset += length;
+
+            sliceLength = expectedDateHeaderPayload.Length + (exactSize ? 0 : expectedContentTypeHeaderPayload.Length - 1);
+            Assert.False(HPackHeaderWriter.ContinueEncodeHeaders(hpackEncoder, headerEnumerator, payload.Slice(offset, sliceLength), out length));
+            Assert.Equal(expectedDateHeaderPayload.Length, length);
+            Assert.Equal(expectedDateHeaderPayload, payload.Slice(offset, length).ToArray());
+
+            offset += length;
+
+            sliceLength = expectedContentTypeHeaderPayload.Length + (exactSize ? 0 : expectedServerHeaderPayload.Length - 1);
+            Assert.False(HPackHeaderWriter.ContinueEncodeHeaders(hpackEncoder, headerEnumerator, payload.Slice(offset, sliceLength), out length));
+            Assert.Equal(expectedContentTypeHeaderPayload.Length, length);
+            Assert.Equal(expectedContentTypeHeaderPayload, payload.Slice(offset, length).ToArray());
+
+            offset += length;
+
+            sliceLength = expectedServerHeaderPayload.Length;
+            Assert.True(HPackHeaderWriter.ContinueEncodeHeaders(hpackEncoder, headerEnumerator, payload.Slice(offset, sliceLength), out length));
+            Assert.Equal(expectedServerHeaderPayload.Length, length);
+            Assert.Equal(expectedServerHeaderPayload, payload.Slice(offset, length).ToArray());
+        }
+
+        [Fact]
+        public void BeginEncodeHeaders_MaxHeaderTableSizeUpdated_SizeUpdateInHeaders()
+        {
+            Span<byte> buffer = new byte[1024 * 16];
+
+            var hpackEncoder = new HPackEncoder();
+            hpackEncoder.UpdateMaxHeaderTableSize(100);
+
+            var enumerator = new Http2HeadersEnumerator();
+
+            // First request
+            enumerator.Initialize(new Dictionary<string, StringValues>());
+            Assert.True(HPackHeaderWriter.BeginEncodeHeaders(hpackEncoder, enumerator, buffer, out var length));
+
+            Assert.Equal(2, length);
+
+            const byte DynamicTableSizeUpdateMask = 0xe0;
+
+            var integerDecoder = new IntegerDecoder();
+            Assert.False(integerDecoder.BeginTryDecode((byte)(buffer[0] & ~DynamicTableSizeUpdateMask), prefixLength: 5, out _));
+            Assert.True(integerDecoder.TryDecode(buffer[1], out var result));
+
+            Assert.Equal(100, result);
+
+            // Second request
+            enumerator.Initialize(new Dictionary<string, StringValues>());
+            Assert.True(HPackHeaderWriter.BeginEncodeHeaders(hpackEncoder, enumerator, buffer, out length));
+
+            Assert.Equal(0, length);
+        }
+
+        private static Http2HeadersEnumerator GetHeadersEnumerator(IEnumerable<KeyValuePair<string, string>> headers)
+        {
+            var groupedHeaders = headers
+                .GroupBy(k => k.Key)
+                .ToDictionary(g => g.Key, g => new StringValues(g.Select(gg => gg.Value).ToArray()));
+
+            var enumerator = new Http2HeadersEnumerator();
+            enumerator.Initialize(groupedHeaders);
+            return enumerator;
+        }
+
+        private EncoderHeaderEntry GetHeaderEntry(HPackEncoder encoder, int index)
+        {
+            var entry = encoder.Head;
+            while (index-- >= 0)
+            {
+                entry = entry.Before;
+            }
+            return entry;
+        }
+
+        private List<EncoderHeaderEntry> GetHeaderEntries(HPackEncoder encoder)
+        {
+            var headers = new List<EncoderHeaderEntry>();
+
+            var entry = encoder.Head;
+            while (entry.Before != encoder.Head)
+            {
+                entry = entry.Before;
+                headers.Add(entry);
+            };
+
+            return headers;
+        }
+    }
+}

src/Servers/Kestrel/Core/test/KestrelServerLimitsTests.cs

@@ -333,11 +333,10 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
         [Theory]
         [InlineData(int.MinValue)]
         [InlineData(-1)]
-        [InlineData(0)]
         public void Http2HeaderTableSizeInvalid(int value)
         {
             var ex = Assert.Throws<ArgumentOutOfRangeException>(() => new KestrelServerLimits().Http2.HeaderTableSize = value);
-            Assert.StartsWith(CoreStrings.GreaterThanZeroRequired, ex.Message);
+            Assert.StartsWith(CoreStrings.GreaterThanOrEqualToZeroRequired, ex.Message);
         }
 
         [Fact]

src/Servers/Kestrel/perf/Kestrel.Performance/Http2ConnectionBenchmarkBase.cs

@@ -8,6 +8,7 @@ using System.Diagnostics;
 using System.IO;
 using System.IO.Pipelines;
 using System.Linq;
+using System.Net.Http.HPack;
 using System.Threading.Tasks;
 using BenchmarkDotNet.Attributes;
 using Microsoft.AspNetCore.Http;
@@ -24,28 +25,25 @@ using Microsoft.Net.Http.Headers;
 
 namespace Microsoft.AspNetCore.Server.Kestrel.Performance
 {
-    public class Http2ConnectionBenchmark
+    public abstract class Http2ConnectionBenchmarkBase
     {
         private MemoryPool<byte> _memoryPool;
         private HttpRequestHeaders _httpRequestHeaders;
         private Http2Connection _connection;
+        private HPackEncoder _hpackEncoder;
         private Http2HeadersEnumerator _requestHeadersEnumerator;
         private int _currentStreamId;
         private byte[] _headersBuffer;
         private DuplexPipe.DuplexPipePair _connectionPair;
         private Http2Frame _httpFrame;
-        private string _responseData;
         private int _dataWritten;
 
-        [Params(0, 10, 1024 * 1024)]
-        public int ResponseDataLength { get; set; }
+        protected abstract Task ProcessRequest(HttpContext httpContext);
 
-        [GlobalSetup]
-        public void GlobalSetup()
+        public virtual void GlobalSetup()
         {
             _memoryPool = SlabMemoryPoolFactory.Create();
             _httpFrame = new Http2Frame();
-            _responseData = new string('!', ResponseDataLength);
 
             var options = new PipeOptions(_memoryPool, readerScheduler: PipeScheduler.Inline, writerScheduler: PipeScheduler.Inline, useSynchronizationContext: false);
 
@@ -58,6 +56,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Performance
             _httpRequestHeaders.Append(HeaderNames.Authority, new StringValues("localhost:80"));
 
             _headersBuffer = new byte[1024 * 16];
+            _hpackEncoder = new HPackEncoder();
 
             var serviceContext = new ServiceContext
             {
@@ -83,7 +82,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Performance
 
             _currentStreamId = 1;
 
-            _ = _connection.ProcessRequestsAsync(new DummyApplication(c => ResponseDataLength == 0 ? Task.CompletedTask : c.Response.WriteAsync(_responseData), new MockHttpContextFactory()));
+            _ = _connection.ProcessRequestsAsync(new DummyApplication(ProcessRequest, new MockHttpContextFactory()));
 
             _connectionPair.Application.Output.Write(Http2Connection.ClientPreface);
             _connectionPair.Application.Output.WriteSettings(new Http2PeerSettings
@@ -102,11 +101,11 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Performance
         }
 
         [Benchmark]
-        public async Task EmptyRequest()
+        public async Task MakeRequest()
         {
             _requestHeadersEnumerator.Initialize(_httpRequestHeaders);
             _requestHeadersEnumerator.MoveNext();
-            _connectionPair.Application.Output.WriteStartStream(streamId: _currentStreamId, _requestHeadersEnumerator, _headersBuffer, endStream: true, frame: _httpFrame);
+            _connectionPair.Application.Output.WriteStartStream(streamId: _currentStreamId, _hpackEncoder, _requestHeadersEnumerator, _headersBuffer, endStream: true, frame: _httpFrame);
             await _connectionPair.Application.Output.FlushAsync();
 
             while (true)

src/Servers/Kestrel/perf/Kestrel.Performance/Http2ConnectionEmptyBenchmark.cs

@@ -0,0 +1,29 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Threading.Tasks;
+using BenchmarkDotNet.Attributes;
+using Microsoft.AspNetCore.Http;
+
+namespace Microsoft.AspNetCore.Server.Kestrel.Performance
+{
+    public class Http2ConnectionBenchmark : Http2ConnectionBenchmarkBase
+    {
+        [Params(0, 128, 1024)]
+        public int ResponseDataLength { get; set; }
+
+        private string _responseData;
+
+        [GlobalSetup]
+        public override void GlobalSetup()
+        {
+            base.GlobalSetup();
+            _responseData = new string('!', ResponseDataLength);
+        }
+
+        protected override Task ProcessRequest(HttpContext httpContext)
+        {
+            return ResponseDataLength == 0 ? Task.CompletedTask : httpContext.Response.WriteAsync(_responseData);
+        }
+    }
+}

src/Servers/Kestrel/perf/Kestrel.Performance/Http2ConnectionHeadersBenchmark.cs

@@ -0,0 +1,48 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Threading.Tasks;
+using BenchmarkDotNet.Attributes;
+using Microsoft.AspNetCore.Http;
+
+namespace Microsoft.AspNetCore.Server.Kestrel.Performance
+{
+    public class Http2ConnectionHeadersBenchmark : Http2ConnectionBenchmarkBase
+    {
+        [Params(1, 4, 32)]
+        public int HeadersCount { get; set; }
+
+        [Params(true, false)]
+        public bool HeadersChange { get; set; }
+
+        private int _headerIndex;
+        private string[] _headerNames;
+
+        [GlobalSetup]
+        public override void GlobalSetup()
+        {
+            base.GlobalSetup();
+
+            _headerNames = new string[HeadersCount * (HeadersChange ? 1000 : 1)];
+            for (var i = 0; i < _headerNames.Length; i++)
+            {
+                _headerNames[i] = "CustomHeader" + i;
+            }
+        }
+
+        protected override Task ProcessRequest(HttpContext httpContext)
+        {
+            for (var i = 0; i < HeadersCount; i++)
+            {
+                var headerName = _headerNames[_headerIndex % HeadersCount];
+                httpContext.Response.Headers[headerName] = "The quick brown fox jumps over the lazy dog.";
+                if (HeadersChange)
+                {
+                    _headerIndex++;
+                }
+            }
+            
+            return Task.CompletedTask;
+        }
+    }
+}

src/Servers/Kestrel/perf/Kestrel.Performance/Http2FrameWriterBenchmark.cs

@@ -36,7 +36,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Performance
                 minResponseDataRate: null,
                 "TestConnectionId",
                 _memoryPool,
-                new KestrelTrace(NullLogger.Instance));
+                new Core.Internal.ServiceContext());
 
             _responseHeaders = new HttpResponseHeaders();
             _responseHeaders.HeaderContentType = "application/json";

src/Servers/Kestrel/shared/test/PipeWriterHttp2FrameExtensions.cs

@@ -25,13 +25,13 @@ namespace Microsoft.AspNetCore.Testing
             writer.Write(payload);
         }
 
-        public static void WriteStartStream(this PipeWriter writer, int streamId, Http2HeadersEnumerator headers, byte[] headerEncodingBuffer, bool endStream, Http2Frame frame = null)
+        public static void WriteStartStream(this PipeWriter writer, int streamId, HPackEncoder hpackEncoder, Http2HeadersEnumerator headers, byte[] headerEncodingBuffer, bool endStream, Http2Frame frame = null)
         {
             frame ??= new Http2Frame();
             frame.PrepareHeaders(Http2HeadersFrameFlags.NONE, streamId);
 
             var buffer = headerEncodingBuffer.AsSpan();
-            var done = HPackHeaderWriter.BeginEncodeHeaders(headers, buffer, out var length);
+            var done = HPackHeaderWriter.BeginEncodeHeaders(hpackEncoder, headers, buffer, out var length);
             frame.PayloadLength = length;
 
             if (done)
@@ -51,7 +51,7 @@ namespace Microsoft.AspNetCore.Testing
             {
                 frame.PrepareContinuation(Http2ContinuationFrameFlags.NONE, streamId);
 
-                done = HPackHeaderWriter.ContinueEncodeHeaders(headers, buffer, out length);
+                done = HPackHeaderWriter.ContinueEncodeHeaders(hpackEncoder, headers, buffer, out length);
                 frame.PayloadLength = length;
 
                 if (done)

src/Servers/Kestrel/test/InMemory.FunctionalTests/Http2/Http2ConnectionTests.cs

@@ -14,10 +14,12 @@ using System.Threading.Tasks;
 using Microsoft.AspNetCore.Connections;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Server.Kestrel.Core.Features;
+using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http;
 using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2;
 using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Infrastructure;
 using Microsoft.AspNetCore.Testing;
 using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Primitives;
 using Microsoft.Net.Http.Headers;
 using Moq;
 using Xunit;
@@ -58,7 +60,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendWindowUpdateAsync(streamId: 1, 65535);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
 
@@ -90,7 +92,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(3, GetHeaders(responseBodySize: 3), endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 2,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 3);
 
@@ -101,7 +103,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(5, GetHeaders(responseBodySize: 3), endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 2,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 5);
 
@@ -197,7 +199,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, _browserRequestHeaders, endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             await ExpectAsync(Http2FrameType.DATA,
@@ -274,7 +276,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, requestHeaders, endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -293,7 +295,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(3, requestHeaders, endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 6,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 3);
 
@@ -323,7 +325,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             serverTcs.SetResult(null);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -356,7 +358,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendDataAsync(1, _helloBytes, endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             await ExpectAsync(Http2FrameType.DATA,
@@ -371,7 +373,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendDataAsync(3, _helloBytes, endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 2,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 3);
             await ExpectAsync(Http2FrameType.DATA,
@@ -415,7 +417,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             appDelegateTcs.TrySetResult(null);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -438,7 +440,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             appDelegateTcs.TrySetResult(null);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 6,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 3);
 
@@ -475,7 +477,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             serverTcs.SetResult(null);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             await ExpectAsync(Http2FrameType.DATA,
@@ -593,7 +595,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendDataAsync(1, new byte[length], endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             // The client's settings is still defaulted to Http2PeerSettings.MinAllowedMaxFrameSize so the echo response will come back in two separate frames
@@ -622,7 +624,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendDataAsync(1, _helloWorldBytes, endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             var dataFrame = await ExpectAsync(Http2FrameType.DATA,
@@ -648,7 +650,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendDataAsync(1, _maxData, endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
 
@@ -691,7 +693,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             }
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
 
@@ -812,7 +814,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendDataAsync(1, _noData, endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             var dataFrame = await ExpectAsync(Http2FrameType.DATA,
@@ -840,7 +842,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendDataAsync(1, _helloBytes, endStream: false);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             var stream1DataFrame1 = await ExpectAsync(Http2FrameType.DATA,
@@ -851,7 +853,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendDataAsync(3, _helloBytes, endStream: false);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 2,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 3);
             var stream3DataFrame1 = await ExpectAsync(Http2FrameType.DATA,
@@ -920,7 +922,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             }
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
 
@@ -972,7 +974,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
                 withStreamId: 0);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 2,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 3);
 
@@ -1050,7 +1052,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             stream3ReadFinished.TrySetResult(null);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 3);
             await ExpectAsync(Http2FrameType.DATA,
@@ -1065,7 +1067,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             stream1ReadFinished.TrySetResult(null);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 2,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             await ExpectAsync(Http2FrameType.DATA,
@@ -1092,7 +1094,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendDataWithPaddingAsync(1, _helloWorldBytes, padLength, endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             var dataFrame = await ExpectAsync(Http2FrameType.DATA,
@@ -1137,7 +1139,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             }
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
 
@@ -1196,7 +1198,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             }
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -1265,7 +1267,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendDataAsync(1, _maxData, endStream: false);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
 
@@ -1440,7 +1442,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, _postRequestHeaders, endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -1482,7 +1484,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(3, _browserRequestHeaders, endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 3);
 
@@ -1532,7 +1534,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(3, _browserRequestHeaders, endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 3);
 
@@ -1636,7 +1638,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, _browserRequestHeaders, endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
 
@@ -1657,7 +1659,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(3, _browserRequestHeaders, endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 6,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 3);
 
@@ -1691,7 +1693,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, _browserRequestHeaders, endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -1706,7 +1708,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, _browserRequestHeaders, endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -1726,7 +1728,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendHeadersWithPaddingAsync(1, _browserRequestHeaders, padLength, endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -1743,7 +1745,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendHeadersWithPriorityAsync(1, _browserRequestHeaders, priority: 42, streamDependency: 0, endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -1763,7 +1765,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendHeadersWithPaddingAndPriorityAsync(1, _browserRequestHeaders, padLength, priority: 42, streamDependency: 0, endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -1789,7 +1791,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
 
             // The second stream should end first, since the first one is waiting for the request body.
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 3);
 
@@ -1801,7 +1803,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendHeadersAsync(1, Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM, _requestTrailers);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 6,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -1835,7 +1837,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendDataAsync(1, _helloBytes, endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             await ExpectAsync(Http2FrameType.DATA,
@@ -1885,17 +1887,163 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             finishSecondRequest.TrySetResult(null);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 3);
 
             finishFirstRequest.TrySetResult(null);
 
+            await ExpectAsync(Http2FrameType.HEADERS,
+                withLength: 6,
+                withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
+                withStreamId: 1);
+
+            await StopConnectionAsync(expectedLastStreamId: 3, ignoreNonGoAwayFrames: false);
+        }
+
+        [Fact]
+        public async Task HEADERS_HeaderTableSizeLimitZero_Received_DynamicTableUpdate()
+        {
+            _serviceContext.ServerOptions.Limits.Http2.HeaderTableSize = 0;
+
+            await InitializeConnectionAsync(_noopApplication, expectedSettingsCount: 4);
+
+            await StartStreamAsync(1, _browserRequestHeaders, endStream: true);
+
+            _hpackEncoder.UpdateMaxHeaderTableSize(0);
+
+            var headerFrame = await ExpectAsync(Http2FrameType.HEADERS,
+                withLength: 38,
+                withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
+                withStreamId: 1);
+
+            const byte DynamicTableSizeUpdateMask = 0xe0;
+
+            var integerDecoder = new IntegerDecoder();
+            Assert.True(integerDecoder.BeginTryDecode((byte)(headerFrame.Payload.Span[0] & ~DynamicTableSizeUpdateMask), prefixLength: 5, out var result));
+
+            // Dynamic table update from the server
+            Assert.Equal(0, result);
+
+            await StartStreamAsync(3, _browserRequestHeaders, endStream: true);
+
+            await ExpectAsync(Http2FrameType.HEADERS,
+                withLength: 37,
+                withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
+                withStreamId: 3);
+
+            await StopConnectionAsync(expectedLastStreamId: 3, ignoreNonGoAwayFrames: false);
+        }
+
+        [Fact]
+        public async Task HEADERS_ResponseSetsIgnoreIndexAndNeverIndexValues_HeadersParsed()
+        {
+            await InitializeConnectionAsync(c =>
+            {
+                c.Response.ContentLength = 0;
+                c.Response.Headers[HeaderNames.SetCookie] = "SetCookie!";
+                c.Response.Headers[HeaderNames.ContentDisposition] = "ContentDisposition!";
+
+                return Task.CompletedTask;
+            });
+
+            await StartStreamAsync(1, _browserRequestHeaders, endStream: true);
+
+            var frame = await ExpectAsync(Http2FrameType.HEADERS,
+                withLength: 90,
+                withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
+                withStreamId: 1);
+
+            var handler = new TestHttpHeadersHandler();
+
+            var hpackDecoder = new HPackDecoder();
+            hpackDecoder.Decode(new ReadOnlySequence<byte>(frame.Payload), endHeaders: true, handler);
+            hpackDecoder.CompleteDecode();
+
+            Assert.Equal("200", handler.Headers[":status"]);
+            Assert.Equal("SetCookie!", handler.Headers[HeaderNames.SetCookie]);
+            Assert.Equal("ContentDisposition!", handler.Headers[HeaderNames.ContentDisposition]);
+            Assert.Equal("0", handler.Headers[HeaderNames.ContentLength]);
+
+            await StartStreamAsync(3, _browserRequestHeaders, endStream: true);
+
+            frame = await ExpectAsync(Http2FrameType.HEADERS,
+                withLength: 60,
+                withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
+                withStreamId: 3);
+
+            handler = new TestHttpHeadersHandler();
+
+            hpackDecoder.Decode(new ReadOnlySequence<byte>(frame.Payload), endHeaders: true, handler);
+            hpackDecoder.CompleteDecode();
+
+            Assert.Equal("200", handler.Headers[":status"]);
+            Assert.Equal("SetCookie!", handler.Headers[HeaderNames.SetCookie]);
+            Assert.Equal("ContentDisposition!", handler.Headers[HeaderNames.ContentDisposition]);
+            Assert.Equal("0", handler.Headers[HeaderNames.ContentLength]);
+
+            await StopConnectionAsync(expectedLastStreamId: 3, ignoreNonGoAwayFrames: false);
+        }
+
+        private class TestHttpHeadersHandler : IHttpHeadersHandler
+        {
+            public readonly Dictionary<string, StringValues> Headers = new Dictionary<string, StringValues>(StringComparer.OrdinalIgnoreCase);
+
+            public void OnHeader(ReadOnlySpan<byte> name, ReadOnlySpan<byte> value)
+            {
+                var nameString = Encoding.ASCII.GetString(name);
+                var valueString = Encoding.ASCII.GetString(value);
+
+                if (Headers.TryGetValue(nameString, out var values))
+                {
+                    var l = values.ToList();
+                    l.Add(valueString);
+
+                    Headers[nameString] = new StringValues(l.ToArray());
+                }
+                else
+                {
+                    Headers[nameString] = new StringValues(valueString);
+                }
+            }
+
+            public void OnHeadersComplete(bool endStream)
+            {
+                throw new NotImplementedException();
+            }
+
+            public void OnStaticIndexedHeader(int index)
+            {
+                throw new NotImplementedException();
+            }
+
+            public void OnStaticIndexedHeader(int index, ReadOnlySpan<byte> value)
+            {
+                throw new NotImplementedException();
+            }
+        }
+
+        [Fact]
+        public async Task HEADERS_DisableDynamicHeaderCompression_HeadersNotCompressed()
+        {
+            _serviceContext.ServerOptions.AllowResponseHeaderCompression = false;
+
+            await InitializeConnectionAsync(_noopApplication);
+
+            await StartStreamAsync(1, _browserRequestHeaders, endStream: true);
+
             await ExpectAsync(Http2FrameType.HEADERS,
                 withLength: 37,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
+            await StartStreamAsync(3, _browserRequestHeaders, endStream: true);
+
+            await ExpectAsync(Http2FrameType.HEADERS,
+                withLength: 37,
+                withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
+                withStreamId: 3);
+
             await StopConnectionAsync(expectedLastStreamId: 3, ignoreNonGoAwayFrames: false);
         }
 
@@ -1918,7 +2066,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             requestBlocker.SetResult(0);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -1961,7 +2109,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, _browserRequestHeaders, endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -2004,7 +2152,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(3, _browserRequestHeaders, endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 3);
 
@@ -2228,7 +2376,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendHeadersAsync(1, Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM, headers);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -2373,7 +2521,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendHeadersAsync(1, Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM, headers);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -2511,7 +2659,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, _browserRequestHeaders, endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
 
@@ -2536,7 +2684,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
 
             // The headers, but not the data for stream 3, can be sent prior to any window updates.
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 2,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 3);
 
@@ -2615,12 +2763,12 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
                 }
             });
 
-            async Task VerifyStreamBackpressure(int streamId)
+            async Task VerifyStreamBackpressure(int streamId, int headersLength)
             {
                 await StartStreamAsync(streamId, _browserRequestHeaders, endStream: true);
 
                 await ExpectAsync(Http2FrameType.HEADERS,
-                    withLength: 33,
+                    withLength: headersLength,
                     withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                     withStreamId: streamId);
 
@@ -2633,9 +2781,9 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
                 Assert.False(writeTasks[streamId].IsCompleted);
             }
 
-            await VerifyStreamBackpressure(1);
-            await VerifyStreamBackpressure(3);
-            await VerifyStreamBackpressure(5);
+            await VerifyStreamBackpressure(1, 32);
+            await VerifyStreamBackpressure(3, 2);
+            await VerifyStreamBackpressure(5, 2);
 
             await SendRstStreamAsync(1);
             await writeTasks[1].DefaultTimeout();
@@ -2913,6 +3061,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
         {
             CreateConnection();
 
+            _connection.ServerSettings.HeaderTableSize = 0;
             _connection.ServerSettings.MaxConcurrentStreams = 1;
             _connection.ServerSettings.MaxHeaderListSize = 4 * 1024;
             _connection.ServerSettings.InitialWindowSize = 1024 * 1024 * 10;
@@ -2923,23 +3072,27 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendSettingsAsync();
 
             var frame = await ExpectAsync(Http2FrameType.SETTINGS,
-                withLength: Http2FrameReader.SettingSize * 3,
+                withLength: Http2FrameReader.SettingSize * 4,
                 withFlags: 0,
                 withStreamId: 0);
 
             // Only non protocol defaults are sent
             var settings = Http2FrameReader.ReadSettings(frame.PayloadSequence);
-            Assert.Equal(3, settings.Count);
+            Assert.Equal(4, settings.Count);
 
             var setting = settings[0];
+            Assert.Equal(Http2SettingsParameter.SETTINGS_HEADER_TABLE_SIZE, setting.Parameter);
+            Assert.Equal(0u, setting.Value);
+
+            setting = settings[1];
             Assert.Equal(Http2SettingsParameter.SETTINGS_MAX_CONCURRENT_STREAMS, setting.Parameter);
             Assert.Equal(1u, setting.Value);
 
-            setting = settings[1];
+            setting = settings[2];
             Assert.Equal(Http2SettingsParameter.SETTINGS_INITIAL_WINDOW_SIZE, setting.Parameter);
             Assert.Equal(1024 * 1024 * 10u, setting.Value);
 
-            setting = settings[2];
+            setting = settings[3];
             Assert.Equal(Http2SettingsParameter.SETTINGS_MAX_HEADER_LIST_SIZE, setting.Parameter);
             Assert.Equal(4 * 1024u, setting.Value);
 
@@ -3100,7 +3253,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
 
             _connection.ServerSettings.MaxFrameSize = Http2PeerSettings.MaxAllowedMaxFrameSize;
             // This includes the default response headers such as :status, etc
-            var defaultResponseHeaderLength = 33;
+            var defaultResponseHeaderLength = 32;
             var headerValueLength = Http2PeerSettings.MinAllowedMaxFrameSize;
             // First byte is always 0
             // Second byte is the length of header name which is 1
@@ -3170,7 +3323,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, _browserRequestHeaders, endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             await ExpectAsync(Http2FrameType.DATA,
@@ -3204,7 +3357,56 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
                 withFlags: (byte)Http2SettingsFrameFlags.ACK,
                 withStreamId: 0);
 
-            await StopConnectionAsync(expectedLastStreamId: 0, ignoreNonGoAwayFrames: false);
+            // Start request
+            await StartStreamAsync(1, _browserRequestHeaders, endStream: true);
+
+            var headerFrame = await ExpectAsync(Http2FrameType.HEADERS,
+                withLength: 36,
+                withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
+                withStreamId: 1);
+
+            // Headers start with :status = 200
+            Assert.Equal(0x88, headerFrame.Payload.Span[0]);
+
+            await StopConnectionAsync(expectedLastStreamId: 1, ignoreNonGoAwayFrames: false);
+        }
+
+        [Fact]
+        public async Task SETTINGS_Received_WithLargeHeaderTableSizeLimit_ChangesHeaderTableSize()
+        {
+            _serviceContext.ServerOptions.Limits.Http2.HeaderTableSize = 40000;
+
+            await InitializeConnectionAsync(_noopApplication, expectedSettingsCount: 4);
+
+            // Update client settings
+            _clientSettings.HeaderTableSize = 65536; // Chrome's default, larger than the 4kb spec default
+            await SendSettingsAsync();
+
+            // ACK
+            await ExpectAsync(Http2FrameType.SETTINGS,
+                withLength: 0,
+                withFlags: (byte)Http2SettingsFrameFlags.ACK,
+                withStreamId: 0);
+
+            // Start request
+            await StartStreamAsync(1, _browserRequestHeaders, endStream: true);
+
+            var headerFrame = await ExpectAsync(Http2FrameType.HEADERS,
+                withLength: 40,
+                withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
+                withStreamId: 1);
+
+            const byte DynamicTableSizeUpdateMask = 0xe0;
+
+            var integerDecoder = new IntegerDecoder();
+            Assert.False(integerDecoder.BeginTryDecode((byte)(headerFrame.Payload.Span[0] & ~DynamicTableSizeUpdateMask), prefixLength: 5, out _));
+            Assert.False(integerDecoder.TryDecode(headerFrame.Payload.Span[1], out _));
+            Assert.False(integerDecoder.TryDecode(headerFrame.Payload.Span[2], out _));
+            Assert.True(integerDecoder.TryDecode(headerFrame.Payload.Span[3], out var result));
+
+            Assert.Equal(40000, result);
+
+            await StopConnectionAsync(expectedLastStreamId: 1, ignoreNonGoAwayFrames: false);
         }
 
         [Fact]
@@ -3319,7 +3521,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
 
             await SendDataAsync(1, _helloBytes, true);
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             await ExpectAsync(Http2FrameType.DATA,
@@ -3332,7 +3534,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
                 withStreamId: 1);
             await SendDataAsync(3, _helloBytes, true);
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 2,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 3);
             await ExpectAsync(Http2FrameType.DATA,
@@ -3405,7 +3607,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, _browserRequestHeaders, endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
 
@@ -3428,13 +3630,13 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             // The headers, but not the data for the stream, can still be sent.
             await StartStreamAsync(3, _browserRequestHeaders, endStream: true);
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 2,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 3);
 
             await StartStreamAsync(5, _browserRequestHeaders, endStream: true);
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 2,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 5);
 
@@ -3493,12 +3695,12 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
                 }
             });
 
-            async Task VerifyStreamBackpressure(int streamId)
+            async Task VerifyStreamBackpressure(int streamId, int headersLength)
             {
                 await StartStreamAsync(streamId, _browserRequestHeaders, endStream: true);
 
                 await ExpectAsync(Http2FrameType.HEADERS,
-                    withLength: 33,
+                    withLength: headersLength,
                     withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                     withStreamId: streamId);
 
@@ -3511,9 +3713,9 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
                 Assert.False(writeTasks[streamId].IsCompleted);
             }
 
-            await VerifyStreamBackpressure(1);
-            await VerifyStreamBackpressure(3);
-            await VerifyStreamBackpressure(5);
+            await VerifyStreamBackpressure(1, 32);
+            await VerifyStreamBackpressure(3, 2);
+            await VerifyStreamBackpressure(5, 2);
 
             // Close all pipes and wait for response to drain
             _pair.Application.Output.Complete();
@@ -3731,7 +3933,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, _browserRequestHeaders, endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
 
@@ -3788,7 +3990,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendDataAsync(1, _helloWorldBytes, endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
 
@@ -3827,7 +4029,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendDataAsync(1, _helloWorldBytes, endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
 
@@ -3879,7 +4081,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, _twoContinuationsRequestHeaders, endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -3906,7 +4108,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
 
             // The second stream should end first, since the first one is waiting for the request body.
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 3);
 
@@ -3929,7 +4131,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendContinuationAsync(1, Http2ContinuationFrameFlags.END_HEADERS, trailers);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 6,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -4027,7 +4229,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendEmptyContinuationFrameAsync(1, Http2ContinuationFrameFlags.END_HEADERS);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -4042,7 +4244,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, _browserRequestHeaders, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 12343,
+                withLength: 12342,
                 withFlags: (byte)Http2HeadersFrameFlags.END_STREAM,
                 withStreamId: 1);
             var continuationFrame1 = await ExpectAsync(Http2FrameType.CONTINUATION,
@@ -4201,7 +4403,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, _browserRequestHeaders, endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -4251,7 +4453,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
 
             await SendDataAsync(1, _helloBytes, true);
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             await ExpectAsync(Http2FrameType.DATA,
@@ -4284,8 +4486,8 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(3, _browserRequestHeaders, endStream: false);
 
             await SendDataAsync(1, _helloBytes, true);
-            await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+            var f = await ExpectAsync(Http2FrameType.HEADERS,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             await ExpectAsync(Http2FrameType.DATA,
@@ -4298,7 +4500,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
                 withStreamId: 1);
             await SendDataAsync(3, _helloBytes, true);
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 2,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 3);
             await ExpectAsync(Http2FrameType.DATA,
@@ -4388,7 +4590,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: false);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 

src/Servers/Kestrel/test/InMemory.FunctionalTests/Http2/Http2StreamTests.cs

@@ -79,7 +79,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 52,
+                withLength: 51,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -104,7 +104,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendHeadersAsync(1, Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM, headers);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 53,
+                withLength: 52,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -131,7 +131,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendHeadersAsync(1, Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM, headers);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 57,
+                withLength: 56,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -159,7 +159,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendHeadersAsync(1, Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM, headers);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 58,
+                withLength: 57,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -193,7 +193,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendHeadersAsync(1, Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM, headers);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 100,
+                withLength: 99,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -235,7 +235,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendHeadersAsync(1, Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM, headers);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -297,7 +297,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -326,7 +326,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -355,7 +355,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 47,
+                withLength: 46,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -386,7 +386,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 47,
+                withLength: 46,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -417,7 +417,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 47,
+                withLength: 46,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -448,7 +448,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 47,
+                withLength: 46,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -570,7 +570,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendDataAsync(1, new byte[12], endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -611,7 +611,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendDataAsync(1, new byte[12], endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -655,7 +655,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendDataAsync(1, new byte[8], endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -698,7 +698,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendDataAsync(1, new byte[8], endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -751,7 +751,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendDataAsync(1, new byte[8], endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -983,7 +983,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendDataAsync(1, new byte[12], endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -1015,7 +1015,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 38,
+                withLength: 37,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             await ExpectAsync(Http2FrameType.RST_STREAM,
@@ -1054,7 +1054,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 38,
+                withLength: 37,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             await ExpectAsync(Http2FrameType.DATA,
@@ -1092,7 +1092,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -1125,7 +1125,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             await ExpectAsync(Http2FrameType.DATA,
@@ -1160,7 +1160,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             await ExpectAsync(Http2FrameType.DATA,
@@ -1198,7 +1198,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             await ExpectAsync(Http2FrameType.DATA,
@@ -1236,7 +1236,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             await ExpectAsync(Http2FrameType.DATA,
@@ -1276,7 +1276,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
 
@@ -1323,7 +1323,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
 
@@ -1361,7 +1361,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             await ExpectAsync(Http2FrameType.DATA,
@@ -1397,7 +1397,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
 
@@ -1441,7 +1441,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 38,
+                withLength: 37,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
 
@@ -1475,7 +1475,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
 
@@ -1508,7 +1508,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 38,
+                withLength: 37,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             await ExpectAsync(Http2FrameType.DATA,
@@ -1552,7 +1552,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendDataAsync(1, new byte[12], endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -1591,7 +1591,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: false);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 41,
+                withLength: 40,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -1634,7 +1634,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendDataAsync(1, new byte[12], endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -1674,7 +1674,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendDataAsync(1, new byte[6], endStream: false);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 41,
+                withLength: 40,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -1733,7 +1733,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendDataAsync(1, new byte[6], endStream: false);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 41,
+                withLength: 40,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -1788,7 +1788,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendDataAsync(1, new byte[12], endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -1814,7 +1814,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, _browserRequestHeaders, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
 
@@ -1852,7 +1852,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, _browserRequestHeaders, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_STREAM | Http2HeadersFrameFlags.END_HEADERS),
                 withStreamId: 1);
 
@@ -1883,7 +1883,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, _browserRequestHeaders, endStream: true);
 
             var headersFrame1 = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS),
                 withStreamId: 1);
             var trailersFrame1 = await ExpectAsync(Http2FrameType.HEADERS,
@@ -1894,12 +1894,12 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(3, _browserRequestHeaders, endStream: true);
 
             var headersFrame2 = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 6,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS),
                 withStreamId: 3);
 
             var trailersFrame2 = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 25,
+                withLength: 1,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 3);
 
@@ -1930,7 +1930,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, _browserRequestHeaders, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
 
@@ -1980,7 +1980,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, _browserRequestHeaders, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
 
@@ -2039,7 +2039,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, _browserRequestHeaders, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
 
@@ -2074,7 +2074,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, _browserRequestHeaders, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
 
@@ -2124,7 +2124,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true).DefaultTimeout();
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1).DefaultTimeout();
 
@@ -2189,7 +2189,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
 
@@ -2235,7 +2235,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -2269,7 +2269,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             await ExpectAsync(Http2FrameType.DATA,
@@ -2532,7 +2532,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, _browserRequestHeaders, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             await ExpectAsync(Http2FrameType.DATA,
@@ -2623,7 +2623,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, _browserRequestHeaders, endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
 
@@ -2671,7 +2671,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
 
             // Just the StatusCode gets written before aborting in the continuation frame
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.NONE,
                 withStreamId: 1);
 
@@ -2700,7 +2700,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -2743,7 +2743,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
 
@@ -2789,7 +2789,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             var dataFrame = await ExpectAsync(Http2FrameType.DATA,
@@ -2835,7 +2835,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             var dataFrame = await ExpectAsync(Http2FrameType.DATA,
@@ -2884,7 +2884,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             var dataFrame = await ExpectAsync(Http2FrameType.DATA,
@@ -2937,7 +2937,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             var dataFrame = await ExpectAsync(Http2FrameType.DATA,
@@ -2987,7 +2987,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             var dataFrame = await ExpectAsync(Http2FrameType.DATA,
@@ -3037,7 +3037,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             var dataFrame = await ExpectAsync(Http2FrameType.DATA,
@@ -3080,7 +3080,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             var dataFrame = await ExpectAsync(Http2FrameType.DATA,
@@ -3126,7 +3126,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             var dataFrame = await ExpectAsync(Http2FrameType.DATA,
@@ -3168,7 +3168,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -3213,7 +3213,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             await ExpectAsync(Http2FrameType.DATA,
@@ -3279,7 +3279,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 38,
+                withLength: 37,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             await ExpectAsync(Http2FrameType.DATA,
@@ -3325,7 +3325,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 38,
+                withLength: 37,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             await ExpectAsync(Http2FrameType.DATA,
@@ -3361,7 +3361,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 38,
+                withLength: 37,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             await ExpectAsync(Http2FrameType.DATA,
@@ -3413,7 +3413,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 38,
+                withLength: 37,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             await ExpectAsync(Http2FrameType.DATA,
@@ -3465,7 +3465,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -3498,7 +3498,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
 
             // Don't receive content length because we called WriteAsync which caused an invalid response
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS | (byte)Http2HeadersFrameFlags.END_STREAM,
                 withStreamId: 1);
 
@@ -3531,7 +3531,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -3583,7 +3583,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -3639,7 +3639,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS),
                 withStreamId: 1);
             var trailersFrame = await ExpectAsync(Http2FrameType.HEADERS,
@@ -3705,7 +3705,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -3761,7 +3761,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS),
                 withStreamId: 1);
             var bodyFrame = await ExpectAsync(Http2FrameType.DATA,
@@ -3826,7 +3826,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -3885,7 +3885,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS),
                 withStreamId: 1);
             var bodyFrame = await ExpectAsync(Http2FrameType.DATA,
@@ -3941,7 +3941,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -4003,7 +4003,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS),
                 withStreamId: 1);
             var bodyFrame = await ExpectAsync(Http2FrameType.DATA,
@@ -4077,7 +4077,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS),
                 withStreamId: 1);
             var bodyFrame = await ExpectAsync(Http2FrameType.DATA,
@@ -4153,7 +4153,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 38,
+                withLength: 37,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS),
                 withStreamId: 1);
             var bodyFrame = await ExpectAsync(Http2FrameType.DATA,
@@ -4224,7 +4224,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 38,
+                withLength: 37,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS),
                 withStreamId: 1);
             var bodyFrame = await ExpectAsync(Http2FrameType.DATA,
@@ -4296,7 +4296,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS),
                 withStreamId: 1);
             var bodyFrame = await ExpectAsync(Http2FrameType.DATA,
@@ -4380,7 +4380,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: false);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS),
                 withStreamId: 1);
             var bodyFrame = await ExpectAsync(Http2FrameType.DATA,
@@ -4461,7 +4461,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS),
                 withStreamId: 1);
             var bodyFrame = await ExpectAsync(Http2FrameType.DATA,
@@ -4548,7 +4548,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, headers, endStream: false);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS),
                 withStreamId: 1);
             var bodyFrame = await ExpectAsync(Http2FrameType.DATA,
@@ -4608,7 +4608,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await StartStreamAsync(1, LatinHeaderData, endStream: true);
 
             var headersFrame = await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 

src/Servers/Kestrel/test/InMemory.FunctionalTests/Http2/Http2TestBase.cs

@@ -121,6 +121,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
 
         internal readonly Http2PeerSettings _clientSettings = new Http2PeerSettings();
         internal readonly HPackDecoder _hpackDecoder;
+        internal readonly HPackEncoder _hpackEncoder;
         private readonly byte[] _headerEncodingBuffer = new byte[Http2PeerSettings.MinAllowedMaxFrameSize];
 
         internal readonly TimeoutControl _timeoutControl;
@@ -165,6 +166,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
         public Http2TestBase()
         {
             _hpackDecoder = new HPackDecoder((int)_clientSettings.HeaderTableSize, MaxRequestHeaderFieldSize);
+            _hpackEncoder = new HPackEncoder();
 
             _timeoutControl = new TimeoutControl(_mockTimeoutHandler.Object);
             _mockTimeoutControl = new Mock<MockTimeoutControlBase>(_timeoutControl) { CallBase = true };
@@ -501,7 +503,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             var tcs = new TaskCompletionSource<object>(TaskCreationOptions.RunContinuationsAsynchronously);
             _runningStreams[streamId] = tcs;
 
-            writableBuffer.WriteStartStream(streamId, GetHeadersEnumerator(headers), _headerEncodingBuffer, endStream);
+            writableBuffer.WriteStartStream(streamId, _hpackEncoder, GetHeadersEnumerator(headers), _headerEncodingBuffer, endStream);
             return FlushAsync(writableBuffer);
         }
 
@@ -541,7 +543,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             extendedHeader[0] = padLength;
             var payload = buffer.Slice(extendedHeaderLength, buffer.Length - padLength - extendedHeaderLength);
 
-            HPackHeaderWriter.BeginEncodeHeaders(GetHeadersEnumerator(headers), payload, out var length);
+            HPackHeaderWriter.BeginEncodeHeaders(_hpackEncoder, GetHeadersEnumerator(headers), payload, out var length);
             var padding = buffer.Slice(extendedHeaderLength + length, padLength);
             padding.Fill(0);
 
@@ -584,7 +586,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             extendedHeader[4] = priority;
             var payload = buffer.Slice(extendedHeaderLength);
 
-            HPackHeaderWriter.BeginEncodeHeaders(GetHeadersEnumerator(headers), payload, out var length);
+            HPackHeaderWriter.BeginEncodeHeaders(_hpackEncoder, GetHeadersEnumerator(headers), payload, out var length);
 
             frame.PayloadLength = extendedHeaderLength + length;
 
@@ -631,7 +633,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             extendedHeader[5] = priority;
             var payload = buffer.Slice(extendedHeaderLength, buffer.Length - padLength - extendedHeaderLength);
 
-            HPackHeaderWriter.BeginEncodeHeaders(GetHeadersEnumerator(headers), payload, out var length);
+            HPackHeaderWriter.BeginEncodeHeaders(_hpackEncoder, GetHeadersEnumerator(headers), payload, out var length);
             var padding = buffer.Slice(extendedHeaderLength + length, padLength);
             padding.Fill(0);
 
@@ -745,7 +747,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
 
             frame.PrepareHeaders(flags, streamId);
             var buffer = _headerEncodingBuffer.AsMemory();
-            var done = HPackHeaderWriter.BeginEncodeHeaders(headersEnumerator, buffer.Span, out var length);
+            var done = HPackHeaderWriter.BeginEncodeHeaders(_hpackEncoder, headersEnumerator, buffer.Span, out var length);
             frame.PayloadLength = length;
 
             Http2FrameWriter.WriteHeader(frame, outputWriter);
@@ -815,7 +817,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
 
             frame.PrepareContinuation(flags, streamId);
             var buffer = _headerEncodingBuffer.AsMemory();
-            var done = HPackHeaderWriter.ContinueEncodeHeaders(headersEnumerator, buffer.Span, out var length);
+            var done = HPackHeaderWriter.ContinueEncodeHeaders(_hpackEncoder, headersEnumerator, buffer.Span, out var length);
             frame.PayloadLength = length;
 
             Http2FrameWriter.WriteHeader(frame, outputWriter);
@@ -843,7 +845,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
 
             frame.PrepareContinuation(flags, streamId);
             var buffer = _headerEncodingBuffer.AsMemory();
-            var done = HPackHeaderWriter.BeginEncodeHeaders(GetHeadersEnumerator(headers), buffer.Span, out var length);
+            var done = HPackHeaderWriter.BeginEncodeHeaders(_hpackEncoder, GetHeadersEnumerator(headers), buffer.Span, out var length);
             frame.PayloadLength = length;
 
             Http2FrameWriter.WriteHeader(frame, outputWriter);

src/Servers/Kestrel/test/InMemory.FunctionalTests/Http2/Http2TimeoutTests.cs

@@ -101,7 +101,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             _mockTimeoutControl.Verify(c => c.SetTimeout(It.IsAny<long>(), TimeoutReason.RequestHeaders), Times.Once);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 36,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 
@@ -283,7 +283,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendDataAsync(1, _helloWorldBytes, endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
 
@@ -336,7 +336,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendDataAsync(1, _maxData, endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
 
@@ -390,7 +390,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendDataAsync(1, _helloWorldBytes, endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             await ExpectAsync(Http2FrameType.DATA,
@@ -445,7 +445,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendDataAsync(1, _maxData, endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             await ExpectAsync(Http2FrameType.DATA,
@@ -501,7 +501,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendDataAsync(1, _maxData, endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
             await ExpectAsync(Http2FrameType.DATA,
@@ -513,7 +513,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendDataAsync(3, _maxData, endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 3);
             await ExpectAsync(Http2FrameType.DATA,
@@ -567,7 +567,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendDataAsync(1, _helloWorldBytes, endStream: false);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
 
@@ -616,7 +616,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendDataAsync(1, _maxData, endStream: false);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
 
@@ -669,7 +669,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendDataAsync(1, _maxData, endStream: false);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
 
@@ -682,7 +682,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendDataAsync(3, _maxData, endStream: false);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 2,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 3);
             await ExpectAsync(Http2FrameType.DATA,
@@ -738,7 +738,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendDataAsync(1, _maxData, endStream: true);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
 
@@ -756,7 +756,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendDataAsync(3, _maxData, endStream: false);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 2,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 3);
             await ExpectAsync(Http2FrameType.DATA,
@@ -813,7 +813,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendDataAsync(1, _helloWorldBytes, endStream: false);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 1);
 
@@ -885,7 +885,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             await SendDataAsync(3, _helloWorldBytes, endStream: false);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 33,
+                withLength: 32,
                 withFlags: (byte)Http2HeadersFrameFlags.END_HEADERS,
                 withStreamId: 3);
             await ExpectAsync(Http2FrameType.DATA,
@@ -902,7 +902,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             backpressureTcs.SetResult(null);
 
             await ExpectAsync(Http2FrameType.HEADERS,
-                withLength: 37,
+                withLength: 6,
                 withFlags: (byte)(Http2HeadersFrameFlags.END_HEADERS | Http2HeadersFrameFlags.END_STREAM),
                 withStreamId: 1);
 

src/Servers/Kestrel/test/Interop.FunctionalTests/HttpClientHttp2InteropTests.cs

@@ -1118,7 +1118,7 @@ namespace Interop.FunctionalTests
                 Assert.Equal(oneKbString + i, response.Headers.GetValues("header" + i).Single());
             }
 
-            Assert.Single(TestSink.Writes.Where(context => context.Message.Contains("sending HEADERS frame for stream ID 1 with length 15612 and flags END_STREAM")));
+            Assert.Single(TestSink.Writes.Where(context => context.Message.Contains("sending HEADERS frame for stream ID 1 with length 15610 and flags END_STREAM")));
             Assert.Equal(2, TestSink.Writes.Where(context => context.Message.Contains("sending CONTINUATION frame for stream ID 1 with length 15585 and flags NONE")).Count());
             Assert.Single(TestSink.Writes.Where(context => context.Message.Contains("sending CONTINUATION frame for stream ID 1 with length 14546 and flags END_HEADERS")));
 

src/Shared/Hpack/EncoderHeaderEntry.cs

@@ -0,0 +1,73 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Diagnostics;
+
+namespace System.Net.Http.HPack
+{
+    [DebuggerDisplay("Name = {Name} Value = {Value}")]
+    internal class EncoderHeaderEntry
+    {
+        // Header name and value
+        public string Name;
+        public string Value;
+
+        // Chained list of headers in the same bucket
+        public EncoderHeaderEntry Next;
+        public int Hash;
+
+        // Compute dynamic table index
+        public int Index;
+
+        // Doubly linked list
+        public EncoderHeaderEntry Before;
+        public EncoderHeaderEntry After;
+
+        /// <summary>
+        /// Initialize header values. An entry will be reinitialized when reused.
+        /// </summary>
+        public void Initialize(int hash, string name, string value, int index, EncoderHeaderEntry next)
+        {
+            Debug.Assert(name != null);
+            Debug.Assert(value != null);
+
+            Name = name;
+            Value = value;
+            Index = index;
+            Hash = hash;
+            Next = next;
+        }
+
+        public uint CalculateSize()
+        {
+            return (uint)HeaderField.GetLength(Name.Length, Value.Length);
+        }
+
+        /// <summary>
+        /// Remove entry from the linked list and reset header values.
+        /// </summary>
+        public void Remove()
+        {
+            Before.After = After;
+            After.Before = Before;
+            Before = null;
+            After = null;
+            Next = null;
+            Hash = 0;
+            Name = null;
+            Value = null;
+        }
+
+        /// <summary>
+        /// Add before an entry in the linked list.
+        /// </summary>
+        public void AddBefore(EncoderHeaderEntry existingEntry)
+        {
+            After = existingEntry;
+            Before = existingEntry.Before;
+            Before.After = this;
+            After.Before = this;
+        }
+    }
+}

src/Shared/Hpack/HPackEncoder.Dynamic.cs

@@ -0,0 +1,295 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+#nullable enable
+using System.Diagnostics;
+
+namespace System.Net.Http.HPack
+{
+    internal partial class HPackEncoder
+    {
+        public const int DefaultHeaderTableSize = 4096;
+
+        // Internal for testing
+        internal readonly EncoderHeaderEntry Head;
+
+        private readonly bool _allowDynamicCompression;
+        private readonly EncoderHeaderEntry[] _headerBuckets;
+        private readonly byte _hashMask;
+        private uint _headerTableSize;
+        private uint _maxHeaderTableSize;
+        private bool _pendingTableSizeUpdate;
+        private EncoderHeaderEntry? _removed;
+
+        public HPackEncoder(bool allowDynamicCompression = true, uint maxHeaderTableSize = DefaultHeaderTableSize)
+        {
+            _allowDynamicCompression = allowDynamicCompression;
+            _maxHeaderTableSize = maxHeaderTableSize;
+            Head = new EncoderHeaderEntry();
+            Head.Initialize(-1, string.Empty, string.Empty, int.MaxValue, null);
+            // Bucket count balances memory usage and the expected low number of headers (constrained by the header table size).
+            // Performance with different bucket counts hasn't been measured in detail.
+            _headerBuckets = new EncoderHeaderEntry[16];
+            _hashMask = (byte)(_headerBuckets.Length - 1);
+            Head.Before = Head.After = Head;
+        }
+
+        public void UpdateMaxHeaderTableSize(uint maxHeaderTableSize)
+        {
+            if (_maxHeaderTableSize != maxHeaderTableSize)
+            {
+                _maxHeaderTableSize = maxHeaderTableSize;
+
+                // Dynamic table size update will be written next HEADERS frame
+                _pendingTableSizeUpdate = true;
+
+                // Check capacity and remove entries that exceed the new capacity
+                EnsureCapacity(0);
+            }
+        }
+
+        public bool EnsureDynamicTableSizeUpdate(Span<byte> buffer, out int length)
+        {
+            // Check if there is a table size update that should be encoded
+            if (_pendingTableSizeUpdate)
+            {
+                bool success = EncodeDynamicTableSizeUpdate((int)_maxHeaderTableSize, buffer, out length);
+                _pendingTableSizeUpdate = false;
+                return success;
+            }
+
+            length = 0;
+            return true;
+        }
+
+        public bool EncodeHeader(Span<byte> buffer, int staticTableIndex, HeaderEncodingHint encodingHint, string name, string value, out int bytesWritten)
+        {
+            Debug.Assert(!_pendingTableSizeUpdate, "Dynamic table size update should be encoded before headers.");
+
+            // Never index sensitive value.
+            if (encodingHint == HeaderEncodingHint.NeverIndex)
+            {
+                int index = ResolveDynamicTableIndex(staticTableIndex, name);
+
+                return index == -1
+                    ? EncodeLiteralHeaderFieldNeverIndexingNewName(name, value, buffer, out bytesWritten)
+                    : EncodeLiteralHeaderFieldNeverIndexing(index, value, buffer, out bytesWritten);
+            }
+
+            // No dynamic table. Only use the static table.
+            if (!_allowDynamicCompression || _maxHeaderTableSize == 0 || encodingHint == HeaderEncodingHint.IgnoreIndex)
+            {
+                return staticTableIndex == -1
+                    ? EncodeLiteralHeaderFieldWithoutIndexingNewName(name, value, buffer, out bytesWritten)
+                    : EncodeLiteralHeaderFieldWithoutIndexing(staticTableIndex, value, buffer, out bytesWritten);
+            }
+
+            // Header is greater than the maximum table size.
+            // Don't attempt to add dynamic header as all existing dynamic headers will be removed.
+            if (HeaderField.GetLength(name.Length, value.Length) > _maxHeaderTableSize)
+            {
+                int index = ResolveDynamicTableIndex(staticTableIndex, name);
+
+                return index == -1
+                    ? EncodeLiteralHeaderFieldWithoutIndexingNewName(name, value, buffer, out bytesWritten)
+                    : EncodeLiteralHeaderFieldWithoutIndexing(index, value, buffer, out bytesWritten);
+            }
+
+            return EncodeDynamicHeader(buffer, staticTableIndex, name, value, out bytesWritten);
+        }
+
+        private int ResolveDynamicTableIndex(int staticTableIndex, string name)
+        {
+            if (staticTableIndex != -1)
+            {
+                // Prefer static table index.
+                return staticTableIndex;
+            }
+
+            return CalculateDynamicTableIndex(name);
+        }
+
+        private bool EncodeDynamicHeader(Span<byte> buffer, int staticTableIndex, string name, string value, out int bytesWritten)
+        {
+            EncoderHeaderEntry? headerField = GetEntry(name, value);
+            if (headerField != null)
+            {
+                // Already exists in dynamic table. Write index.
+                int index = CalculateDynamicTableIndex(headerField.Index);
+                return EncodeIndexedHeaderField(index, buffer, out bytesWritten);
+            }
+            else
+            {
+                // Doesn't exist in dynamic table. Add new entry to dynamic table.
+                uint headerSize = (uint)HeaderField.GetLength(name.Length, value.Length);
+
+                int index = ResolveDynamicTableIndex(staticTableIndex, name);
+                bool success = index == -1
+                    ? EncodeLiteralHeaderFieldIndexingNewName(name, value, buffer, out bytesWritten)
+                    : EncodeLiteralHeaderFieldIndexing(index, value, buffer, out bytesWritten);
+
+                if (success)
+                {
+                    EnsureCapacity(headerSize);
+                    AddHeaderEntry(name, value, headerSize);
+                }
+
+                return success;
+            }
+        }
+
+        /// <summary>
+        /// Ensure there is capacity for the new header. If there is not enough capacity then remove
+        /// existing headers until space is available.
+        /// </summary>
+        private void EnsureCapacity(uint headerSize)
+        {
+            Debug.Assert(headerSize <= _maxHeaderTableSize, "Header is bigger than dynamic table size.");
+
+            while (_maxHeaderTableSize - _headerTableSize < headerSize)
+            {
+                EncoderHeaderEntry? removed = RemoveHeaderEntry();
+                Debug.Assert(removed != null);
+
+                // Removed entries are tracked to be reused.
+                PushRemovedEntry(removed);
+            }
+        }
+
+        private EncoderHeaderEntry? GetEntry(string name, string value)
+        {
+            if (_headerTableSize == 0)
+            {
+                return null;
+            }
+            int hash = name.GetHashCode();
+            int bucketIndex = CalculateBucketIndex(hash);
+            for (EncoderHeaderEntry? e = _headerBuckets[bucketIndex]; e != null; e = e.Next)
+            {
+                // We've already looked up entries based on a hash of the name.
+                // Compare value before name as it is more likely to be different.
+                if (e.Hash == hash &&
+                    string.Equals(value, e.Value, StringComparison.Ordinal) &&
+                    string.Equals(name, e.Name, StringComparison.Ordinal))
+                {
+                    return e;
+                }
+            }
+            return null;
+        }
+
+        private int CalculateDynamicTableIndex(string name)
+        {
+            if (_headerTableSize == 0)
+            {
+                return -1;
+            }
+            int hash = name.GetHashCode();
+            int bucketIndex = CalculateBucketIndex(hash);
+            for (EncoderHeaderEntry? e = _headerBuckets[bucketIndex]; e != null; e = e.Next)
+            {
+                if (e.Hash == hash && string.Equals(name, e.Name, StringComparison.Ordinal))
+                {
+                    return CalculateDynamicTableIndex(e.Index);
+                }
+            }
+            return -1;
+        }
+
+        private int CalculateDynamicTableIndex(int index)
+        {
+            return index == -1 ? -1 : index - Head.Before.Index + 1 + H2StaticTable.Count;
+        }
+
+        private void AddHeaderEntry(string name, string value, uint headerSize)
+        {
+            Debug.Assert(headerSize <= _maxHeaderTableSize, "Header is bigger than dynamic table size.");
+            Debug.Assert(headerSize <= _maxHeaderTableSize - _headerTableSize, "Not enough room in dynamic table.");
+
+            int hash = name.GetHashCode();
+            int bucketIndex = CalculateBucketIndex(hash);
+            EncoderHeaderEntry? oldEntry = _headerBuckets[bucketIndex];
+            // Attempt to reuse removed entry
+            EncoderHeaderEntry? newEntry = PopRemovedEntry() ?? new EncoderHeaderEntry();
+            newEntry.Initialize(hash, name, value, Head.Before.Index - 1, oldEntry);
+            _headerBuckets[bucketIndex] = newEntry;
+            newEntry.AddBefore(Head);
+            _headerTableSize += headerSize;
+        }
+
+        private void PushRemovedEntry(EncoderHeaderEntry removed)
+        {
+            if (_removed != null)
+            {
+                removed.Next = _removed;
+            }
+            _removed = removed;
+        }
+
+        private EncoderHeaderEntry? PopRemovedEntry()
+        {
+            if (_removed != null)
+            {
+                EncoderHeaderEntry? removed = _removed;
+                _removed = _removed.Next;
+                return removed;
+            }
+
+            return null;
+        }
+
+        /// <summary>
+        /// Remove the oldest entry.
+        /// </summary>
+        private EncoderHeaderEntry? RemoveHeaderEntry()
+        {
+            if (_headerTableSize == 0)
+            {
+                return null;
+            }
+            EncoderHeaderEntry? eldest = Head.After;
+            int hash = eldest.Hash;
+            int bucketIndex = CalculateBucketIndex(hash);
+            EncoderHeaderEntry? prev = _headerBuckets[bucketIndex];
+            EncoderHeaderEntry? e = prev;
+            while (e != null)
+            {
+                EncoderHeaderEntry next = e.Next;
+                if (e == eldest)
+                {
+                    if (prev == eldest)
+                    {
+                        _headerBuckets[bucketIndex] = next;
+                    }
+                    else
+                    {
+                        prev.Next = next;
+                    }
+                    _headerTableSize -= eldest.CalculateSize();
+                    eldest.Remove();
+                    return eldest;
+                }
+                prev = e;
+                e = next;
+            }
+            return null;
+        }
+
+        private int CalculateBucketIndex(int hash)
+        {
+            return hash & _hashMask;
+        }
+    }
+
+    /// <summary>
+    /// Hint for how the header should be encoded as HPack. This value can be overriden.
+    /// For example, a header that is larger than the dynamic table won't be indexed.
+    /// </summary>
+    internal enum HeaderEncodingHint
+    {
+        Index,
+        IgnoreIndex,
+        NeverIndex
+    }
+}

src/Shared/Hpack/README.md

@@ -0,0 +1,3 @@
+HPack dynamic compression. These files are kept separate to help avoid ASP.NET Core dependencies being added to them.
+
+Runtime currently doesn't implement HPack dynamic compression. These files will move into runtime shareable code in the future when support is added to runtime.

src/Shared/Hpack/StatusCodes.cs

@@ -0,0 +1,151 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Globalization;
+using System.Text;
+
+namespace System.Net.Http.HPack
+{
+    internal static partial class StatusCodes
+    {
+        public static string ToStatusString(int statusCode)
+        {
+            switch (statusCode)
+            {
+                case (int)HttpStatusCode.Continue:
+                    return "100";
+                case (int)HttpStatusCode.SwitchingProtocols:
+                    return "101";
+                case (int)HttpStatusCode.Processing:
+                    return "102";
+
+                case (int)HttpStatusCode.OK:
+                    return "200";
+                case (int)HttpStatusCode.Created:
+                    return "201";
+                case (int)HttpStatusCode.Accepted:
+                    return "202";
+                case (int)HttpStatusCode.NonAuthoritativeInformation:
+                    return "203";
+                case (int)HttpStatusCode.NoContent:
+                    return "204";
+                case (int)HttpStatusCode.ResetContent:
+                    return "205";
+                case (int)HttpStatusCode.PartialContent:
+                    return "206";
+                case (int)HttpStatusCode.MultiStatus:
+                    return "207";
+                case (int)HttpStatusCode.AlreadyReported:
+                    return "208";
+                case (int)HttpStatusCode.IMUsed:
+                    return "226";
+
+                case (int)HttpStatusCode.MultipleChoices:
+                    return "300";
+                case (int)HttpStatusCode.MovedPermanently:
+                    return "301";
+                case (int)HttpStatusCode.Found:
+                    return "302";
+                case (int)HttpStatusCode.SeeOther:
+                    return "303";
+                case (int)HttpStatusCode.NotModified:
+                    return "304";
+                case (int)HttpStatusCode.UseProxy:
+                    return "305";
+                case (int)HttpStatusCode.Unused:
+                    return "306";
+                case (int)HttpStatusCode.TemporaryRedirect:
+                    return "307";
+                case (int)HttpStatusCode.PermanentRedirect:
+                    return "308";
+
+                case (int)HttpStatusCode.BadRequest:
+                    return "400";
+                case (int)HttpStatusCode.Unauthorized:
+                    return "401";
+                case (int)HttpStatusCode.PaymentRequired:
+                    return "402";
+                case (int)HttpStatusCode.Forbidden:
+                    return "403";
+                case (int)HttpStatusCode.NotFound:
+                    return "404";
+                case (int)HttpStatusCode.MethodNotAllowed:
+                    return "405";
+                case (int)HttpStatusCode.NotAcceptable:
+                    return "406";
+                case (int)HttpStatusCode.ProxyAuthenticationRequired:
+                    return "407";
+                case (int)HttpStatusCode.RequestTimeout:
+                    return "408";
+                case (int)HttpStatusCode.Conflict:
+                    return "409";
+                case (int)HttpStatusCode.Gone:
+                    return "410";
+                case (int)HttpStatusCode.LengthRequired:
+                    return "411";
+                case (int)HttpStatusCode.PreconditionFailed:
+                    return "412";
+                case (int)HttpStatusCode.RequestEntityTooLarge:
+                    return "413";
+                case (int)HttpStatusCode.RequestUriTooLong:
+                    return "414";
+                case (int)HttpStatusCode.UnsupportedMediaType:
+                    return "415";
+                case (int)HttpStatusCode.RequestedRangeNotSatisfiable:
+                    return "416";
+                case (int)HttpStatusCode.ExpectationFailed:
+                    return "417";
+                case (int)418:
+                    return "418";
+                case (int)419:
+                    return "419";
+                case (int)HttpStatusCode.MisdirectedRequest:
+                    return "421";
+                case (int)HttpStatusCode.UnprocessableEntity:
+                    return "422";
+                case (int)HttpStatusCode.Locked:
+                    return "423";
+                case (int)HttpStatusCode.FailedDependency:
+                    return "424";
+                case (int)HttpStatusCode.UpgradeRequired:
+                    return "426";
+                case (int)HttpStatusCode.PreconditionRequired:
+                    return "428";
+                case (int)HttpStatusCode.TooManyRequests:
+                    return "429";
+                case (int)HttpStatusCode.RequestHeaderFieldsTooLarge:
+                    return "431";
+                case (int)HttpStatusCode.UnavailableForLegalReasons:
+                    return "451";
+
+                case (int)HttpStatusCode.InternalServerError:
+                    return "500";
+                case (int)HttpStatusCode.NotImplemented:
+                    return "501";
+                case (int)HttpStatusCode.BadGateway:
+                    return "502";
+                case (int)HttpStatusCode.ServiceUnavailable:
+                    return "503";
+                case (int)HttpStatusCode.GatewayTimeout:
+                    return "504";
+                case (int)HttpStatusCode.HttpVersionNotSupported:
+                    return "505";
+                case (int)HttpStatusCode.VariantAlsoNegotiates:
+                    return "506";
+                case (int)HttpStatusCode.InsufficientStorage:
+                    return "507";
+                case (int)HttpStatusCode.LoopDetected:
+                    return "508";
+                case (int)HttpStatusCode.NotExtended:
+                    return "510";
+                case (int)HttpStatusCode.NetworkAuthenticationRequired:
+                    return "511";
+
+                default:
+                    return statusCode.ToString(CultureInfo.InvariantCulture);
+
+            }
+        }
+    }
+}

src/Shared/runtime/Http2/Hpack/HPackEncoder.cs

@@ -8,7 +8,7 @@ using System.Diagnostics;
 
 namespace System.Net.Http.HPack
 {
-    internal static class HPackEncoder
+    internal partial class HPackEncoder
     {
         // Things we should add:
         // * Huffman encoding
@@ -109,6 +109,70 @@ namespace System.Net.Http.HPack
             return false;
         }
 
+        /// <summary>Encodes a "Literal Header Field never Indexing".</summary>
+        public static bool EncodeLiteralHeaderFieldNeverIndexing(int index, string value, Span<byte> destination, out int bytesWritten)
+        {
+            // From https://tools.ietf.org/html/rfc7541#section-6.2.3
+            // ------------------------------------------------------
+            //   0   1   2   3   4   5   6   7
+            // +---+---+---+---+---+---+---+---+
+            // | 0 | 0 | 0 | 1 |  Index (4+)   |
+            // +---+---+-----------------------+
+            // | H |     Value Length (7+)     |
+            // +---+---------------------------+
+            // | Value String (Length octets)  |
+            // +-------------------------------+
+
+            if ((uint)destination.Length >= 2)
+            {
+                destination[0] = 0x10;
+                if (IntegerEncoder.Encode(index, 4, destination, out int indexLength))
+                {
+                    Debug.Assert(indexLength >= 1);
+                    if (EncodeStringLiteral(value, destination.Slice(indexLength), out int nameLength))
+                    {
+                        bytesWritten = indexLength + nameLength;
+                        return true;
+                    }
+                }
+            }
+
+            bytesWritten = 0;
+            return false;
+        }
+
+        /// <summary>Encodes a "Literal Header Field with Indexing".</summary>
+        public static bool EncodeLiteralHeaderFieldIndexing(int index, string value, Span<byte> destination, out int bytesWritten)
+        {
+            // From https://tools.ietf.org/html/rfc7541#section-6.2.2
+            // ------------------------------------------------------
+            //   0   1   2   3   4   5   6   7
+            // +---+---+---+---+---+---+---+---+
+            // | 0 | 1 |      Index (6+)       |
+            // +---+---+-----------------------+
+            // | H |     Value Length (7+)     |
+            // +---+---------------------------+
+            // | Value String (Length octets)  |
+            // +-------------------------------+
+
+            if ((uint)destination.Length >= 2)
+            {
+                destination[0] = 0x40;
+                if (IntegerEncoder.Encode(index, 6, destination, out int indexLength))
+                {
+                    Debug.Assert(indexLength >= 1);
+                    if (EncodeStringLiteral(value, destination.Slice(indexLength), out int nameLength))
+                    {
+                        bytesWritten = indexLength + nameLength;
+                        return true;
+                    }
+                }
+            }
+
+            bytesWritten = 0;
+            return false;
+        }
+
         /// <summary>
         /// Encodes a "Literal Header Field without Indexing", but only the index portion;
         /// a subsequent call to <c>EncodeStringLiteral</c> must be used to encode the associated value.
@@ -144,6 +208,27 @@ namespace System.Net.Http.HPack
             return false;
         }
 
+        /// <summary>Encodes a "Literal Header Field with Indexing - New Name".</summary>
+        public static bool EncodeLiteralHeaderFieldIndexingNewName(string name, string value, Span<byte> destination, out int bytesWritten)
+        {
+            // From https://tools.ietf.org/html/rfc7541#section-6.2.2
+            // ------------------------------------------------------
+            //   0   1   2   3   4   5   6   7
+            // +---+---+---+---+---+---+---+---+
+            // | 0 | 1 |           0           |
+            // +---+---+-----------------------+
+            // | H |     Name Length (7+)      |
+            // +---+---------------------------+
+            // |  Name String (Length octets)  |
+            // +---+---------------------------+
+            // | H |     Value Length (7+)     |
+            // +---+---------------------------+
+            // | Value String (Length octets)  |
+            // +-------------------------------+
+
+            return EncodeLiteralHeaderNewNameCore(0x40, name, value, destination, out bytesWritten);
+        }
+
         /// <summary>Encodes a "Literal Header Field without Indexing - New Name".</summary>
         public static bool EncodeLiteralHeaderFieldWithoutIndexingNewName(string name, string value, Span<byte> destination, out int bytesWritten)
         {
@@ -162,9 +247,35 @@ namespace System.Net.Http.HPack
             // | Value String (Length octets)  |
             // +-------------------------------+
 
+            return EncodeLiteralHeaderNewNameCore(0, name, value, destination, out bytesWritten);
+        }
+
+        /// <summary>Encodes a "Literal Header Field never Indexing - New Name".</summary>
+        public static bool EncodeLiteralHeaderFieldNeverIndexingNewName(string name, string value, Span<byte> destination, out int bytesWritten)
+        {
+            // From https://tools.ietf.org/html/rfc7541#section-6.2.3
+            // ------------------------------------------------------
+            //   0   1   2   3   4   5   6   7
+            // +---+---+---+---+---+---+---+---+
+            // | 0 | 0 | 0 | 1 |       0       |
+            // +---+---+-----------------------+
+            // | H |     Name Length (7+)      |
+            // +---+---------------------------+
+            // |  Name String (Length octets)  |
+            // +---+---------------------------+
+            // | H |     Value Length (7+)     |
+            // +---+---------------------------+
+            // | Value String (Length octets)  |
+            // +-------------------------------+
+
+            return EncodeLiteralHeaderNewNameCore(0x10, name, value, destination, out bytesWritten);
+        }
+
+        private static bool EncodeLiteralHeaderNewNameCore(byte mask, string name, string value, Span<byte> destination, out int bytesWritten)
+        {
             if ((uint)destination.Length >= 3)
             {
-                destination[0] = 0;
+                destination[0] = mask;
                 if (EncodeLiteralHeaderName(name, destination.Slice(1), out int nameLength) &&
                     EncodeStringLiteral(value, destination.Slice(1 + nameLength), out int valueLength))
                 {
@@ -372,6 +483,25 @@ namespace System.Net.Http.HPack
             return false;
         }
 
+        public static bool EncodeDynamicTableSizeUpdate(int value, Span<byte> destination, out int bytesWritten)
+        {
+            // From https://tools.ietf.org/html/rfc7541#section-6.3
+            // ----------------------------------------------------
+            //   0   1   2   3   4   5   6   7
+            // +---+---+---+---+---+---+---+---+
+            // | 0 | 0 | 1 |   Max size (5+)   |
+            // +---+---------------------------+
+
+            if (destination.Length != 0)
+            {
+                destination[0] = 0x20;
+                return IntegerEncoder.Encode(value, 5, destination, out bytesWritten);
+            }
+
+            bytesWritten = 0;
+            return false;
+        }
+
         public static bool EncodeStringLiterals(ReadOnlySpan<string> values, string? separator, Span<byte> destination, out int bytesWritten)
         {
             bytesWritten = 0;

src/Shared/runtime/Http2/Hpack/StatusCodes.cs

@@ -7,7 +7,7 @@ using System.Text;
 
 namespace System.Net.Http.HPack
 {
-    internal static class StatusCodes
+    internal static partial class StatusCodes
     {
         // This uses C# compiler's ability to refer to static data directly. For more information see https://vcsjones.dev/2019/02/01/csharp-readonly-span-bytes-static