Better context pooling (#12385)

- This change goes from pooling just the HttpContext to pooling the entire TContext. In the past this was a huge struct that got copied around and now it can be a class. Servers can provide the storage for the TContext via a new `IHostContextContainer<TContext>` interface. 
- Removed IDefaultHttpContextContainer since it's been superseded by IHostContextContainer
- Move DefaultHttpContextFactory to Hosting to take advantage of internal methods
- Also handle a null FeatureCollection and null HttpContext and throw a better exception

src/Hosting/Hosting/ref/Microsoft.AspNetCore.Hosting.netcoreapp3.0.cs

@@ -85,6 +85,15 @@ namespace Microsoft.AspNetCore.Hosting.StaticWebAssets
         public static void UseStaticWebAssets(Microsoft.AspNetCore.Hosting.IWebHostEnvironment environment, Microsoft.Extensions.Configuration.IConfiguration configuration) { }
     }
 }
+namespace Microsoft.AspNetCore.Http
+{
+    public partial class DefaultHttpContextFactory : Microsoft.AspNetCore.Http.IHttpContextFactory
+    {
+        public DefaultHttpContextFactory(System.IServiceProvider serviceProvider) { }
+        public Microsoft.AspNetCore.Http.HttpContext Create(Microsoft.AspNetCore.Http.Features.IFeatureCollection featureCollection) { throw null; }
+        public void Dispose(Microsoft.AspNetCore.Http.HttpContext httpContext) { }
+    }
+}
 namespace Microsoft.Extensions.Hosting
 {
     public static partial class GenericHostWebHostBuilderExtensions

src/Hosting/Hosting/src/Http/DefaultHttpContextFactory.cs

@@ -2,6 +2,8 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.Diagnostics;
+using System.Runtime.CompilerServices;
 using Microsoft.AspNetCore.Http.Features;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Options;
@@ -26,12 +28,30 @@ namespace Microsoft.AspNetCore.Http
 
         public HttpContext Create(IFeatureCollection featureCollection)
         {
-            if (featureCollection == null)
+            if (featureCollection is null)
             {
                 throw new ArgumentNullException(nameof(featureCollection));
             }
 
-            var httpContext = CreateHttpContext(featureCollection);
+            var httpContext = new DefaultHttpContext(featureCollection);
+            Initialize(httpContext);
+            return httpContext;
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        internal void Initialize(DefaultHttpContext httpContext, IFeatureCollection featureCollection)
+        {
+            Debug.Assert(featureCollection != null);
+            Debug.Assert(httpContext != null);
+
+            httpContext.Initialize(featureCollection);
+
+            Initialize(httpContext);
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        private DefaultHttpContext Initialize(DefaultHttpContext httpContext)
+        {
             if (_httpContextAccessor != null)
             {
                 _httpContextAccessor.HttpContext = httpContext;
@@ -43,16 +63,6 @@ namespace Microsoft.AspNetCore.Http
             return httpContext;
         }
 
-        private static DefaultHttpContext CreateHttpContext(IFeatureCollection featureCollection)
-        {
-            if (featureCollection is IDefaultHttpContextContainer container)
-            {
-                return container.HttpContext;
-            }
-
-            return new DefaultHttpContext(featureCollection);
-        }
-
         public void Dispose(HttpContext httpContext)
         {
             if (_httpContextAccessor != null)
@@ -60,5 +70,15 @@ namespace Microsoft.AspNetCore.Http
                 _httpContextAccessor.HttpContext = null;
             }
         }
+
+        internal void Dispose(DefaultHttpContext httpContext)
+        {
+            if (_httpContextAccessor != null)
+            {
+                _httpContextAccessor.HttpContext = null;
+            }
+
+            httpContext.Uninitialize();
+        }
     }
 }

src/Hosting/Hosting/src/Internal/HostingApplication.cs

@@ -5,6 +5,7 @@ using System;
 using System.Diagnostics;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Hosting.Server;
+using Microsoft.AspNetCore.Hosting.Server.Abstractions;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Http.Features;
 using Microsoft.Extensions.Logging;
@@ -15,6 +16,7 @@ namespace Microsoft.AspNetCore.Hosting
     {
         private readonly RequestDelegate _application;
         private readonly IHttpContextFactory _httpContextFactory;
+        private readonly DefaultHttpContextFactory _defaultHttpContextFactory;
         private HostingApplicationDiagnostics _diagnostics;
 
         public HostingApplication(
@@ -25,19 +27,58 @@ namespace Microsoft.AspNetCore.Hosting
         {
             _application = application;
             _diagnostics = new HostingApplicationDiagnostics(logger, diagnosticSource);
-            _httpContextFactory = httpContextFactory;
+            if (httpContextFactory is DefaultHttpContextFactory factory)
+            {
+                _defaultHttpContextFactory = factory;
+            }
+            else
+            {
+                _httpContextFactory = httpContextFactory;
+            }
         }
 
         // Set up the request
         public Context CreateContext(IFeatureCollection contextFeatures)
         {
-            var context = new Context();
+            Context hostContext;
-            var httpContext = _httpContextFactory.Create(contextFeatures);
+            if (contextFeatures is IHostContextContainer<Context> container)
+            {
+                hostContext = container.HostContext;
+                if (hostContext is null)
+                {
+                    hostContext = new Context();
+                    container.HostContext = hostContext;
+                }
+            }
+            else
+            {
+                // Server doesn't support pooling, so create a new Context
+                hostContext = new Context();
+            }
 
-            _diagnostics.BeginRequest(httpContext, ref context);
+            HttpContext httpContext;
+            if (_defaultHttpContextFactory != null)
+            {
+                var defaultHttpContext = (DefaultHttpContext)hostContext.HttpContext;
+                if (defaultHttpContext is null)
+                {
+                    httpContext = _defaultHttpContextFactory.Create(contextFeatures);
+                    hostContext.HttpContext = httpContext;
+                }
+                else
+                {
+                    _defaultHttpContextFactory.Initialize(defaultHttpContext, contextFeatures);
+                    httpContext = defaultHttpContext;
+                }
+            }
+            else
+            {
+                httpContext = _httpContextFactory.Create(contextFeatures);
+                hostContext.HttpContext = httpContext;
+            }
 
-            context.HttpContext = httpContext;
+            _diagnostics.BeginRequest(httpContext, hostContext);
-            return context;
+            return hostContext;
         }
 
         // Execute the request
@@ -51,18 +92,44 @@ namespace Microsoft.AspNetCore.Hosting
         {
             var httpContext = context.HttpContext;
             _diagnostics.RequestEnd(httpContext, exception, context);
-            _httpContextFactory.Dispose(httpContext);
+
+            if (_defaultHttpContextFactory != null)
+            {
+                _defaultHttpContextFactory.Dispose((DefaultHttpContext)httpContext);
+            }
+            else
+            {
+                _httpContextFactory.Dispose(httpContext);
+            }
+
             _diagnostics.ContextDisposed(context);
+
+            // Reset the context as it may be pooled
+            context.Reset();
         }
 
-        internal struct Context
+
+        internal class Context
         {
             public HttpContext HttpContext { get; set; }
             public IDisposable Scope { get; set; }
-            public long StartTimestamp { get; set; }
-            public bool EventLogEnabled { get; set; }
             public Activity Activity { get; set; }
+
+            public long StartTimestamp { get; set; }
             internal bool HasDiagnosticListener { get; set; }
+            public bool EventLogEnabled { get; set; }
+
+            public void Reset()
+            {
+                // Not resetting HttpContext here as we pool it on the Context
+
+                Scope = null;
+                Activity = null;
+
+                StartTimestamp = 0;
+                HasDiagnosticListener = false;
+                EventLogEnabled = false;
+            }
         }
     }
 }

src/Hosting/Hosting/src/Internal/HostingApplicationDiagnostics.cs

@@ -33,7 +33,7 @@ namespace Microsoft.AspNetCore.Hosting
         }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public void BeginRequest(HttpContext httpContext, ref HostingApplication.Context context)
+        public void BeginRequest(HttpContext httpContext, HostingApplication.Context context)
         {
             long startTimestamp = 0;
 

src/Hosting/Hosting/test/Http/DefaultHttpContextFactoryTests.cs

@@ -1,11 +1,8 @@
 // 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.IO;
 using Microsoft.AspNetCore.Http.Features;
 using Microsoft.Extensions.DependencyInjection;
-using Microsoft.Extensions.Options;
 using Xunit;
 
 namespace Microsoft.AspNetCore.Http

src/Hosting/Hosting/test/WebHostTests.cs

@@ -883,23 +883,21 @@ namespace Microsoft.AspNetCore.Hosting
         public async Task WebHost_CreatesDefaultRequestIdentifierFeature_IfNotPresent()
         {
             // Arrange
-            HttpContext httpContext = null;
+            var requestDelegate = new RequestDelegate(httpContext =>
-            var requestDelegate = new RequestDelegate(innerHttpContext =>
-                {
-                    httpContext = innerHttpContext;
-                    return Task.FromResult(0);
-                });
-
-            using (var host = CreateHost(requestDelegate))
             {
-                // Act
-                await host.StartAsync();
-
                 // Assert
                 Assert.NotNull(httpContext);
                 var featuresTraceIdentifier = httpContext.Features.Get<IHttpRequestIdentifierFeature>().TraceIdentifier;
                 Assert.False(string.IsNullOrWhiteSpace(httpContext.TraceIdentifier));
                 Assert.Same(httpContext.TraceIdentifier, featuresTraceIdentifier);
+
+                return Task.CompletedTask;
+            });
+
+            using (var host = CreateHost(requestDelegate))
+            {
+                // Act
+                await host.StartAsync();
             }
         }
 
@@ -907,13 +905,15 @@ namespace Microsoft.AspNetCore.Hosting
         public async Task WebHost_DoesNot_CreateDefaultRequestIdentifierFeature_IfPresent()
         {
             // Arrange
-            HttpContext httpContext = null;
-            var requestDelegate = new RequestDelegate(innerHttpContext =>
-            {
-                httpContext = innerHttpContext;
-                return Task.FromResult(0);
-            });
             var requestIdentifierFeature = new StubHttpRequestIdentifierFeature();
+            var requestDelegate = new RequestDelegate(httpContext =>
+            {
+                // Assert
+                Assert.NotNull(httpContext);
+                Assert.Same(requestIdentifierFeature, httpContext.Features.Get<IHttpRequestIdentifierFeature>());
+
+                return Task.CompletedTask;
+            });
 
             using (var host = CreateHost(requestDelegate))
             {
@@ -926,10 +926,6 @@ namespace Microsoft.AspNetCore.Hosting
                 };
                 // Act
                 await host.StartAsync();
-
-                // Assert
-                Assert.NotNull(httpContext);
-                Assert.Same(requestIdentifierFeature, httpContext.Features.Get<IHttpRequestIdentifierFeature>());
             }
         }
 
@@ -949,6 +945,36 @@ namespace Microsoft.AspNetCore.Hosting
             }
         }
 
+        [Fact]
+        public async Task WebHost_HttpContextUseAfterRequestEnd_Fails()
+        {
+            // Arrange
+            HttpContext capturedContext = null;
+            HttpRequest capturedRequest = null;
+            var requestDelegate = new RequestDelegate(httpContext =>
+            {
+                capturedContext = httpContext;
+                capturedRequest = httpContext.Request;
+
+                return Task.CompletedTask;
+            });
+
+            using (var host = CreateHost(requestDelegate))
+            {
+                // Act
+                await host.StartAsync();
+
+                // Assert
+                Assert.NotNull(capturedContext);
+                Assert.NotNull(capturedRequest);
+
+                Assert.Throws<ObjectDisposedException>(() => capturedContext.TraceIdentifier);
+                Assert.Throws<ObjectDisposedException>(() => capturedContext.Features.Get<IHttpRequestIdentifierFeature>());
+
+                Assert.Throws<ObjectDisposedException>(() => capturedRequest.Scheme);
+            }
+        }
+
         public class CountStartup
         {
             public static int ConfigureServicesCount;

src/Hosting/Server.Abstractions/ref/Microsoft.AspNetCore.Hosting.Server.Abstractions.netcoreapp3.0.cs

@@ -27,6 +27,13 @@ namespace Microsoft.AspNetCore.Hosting.Server
         public bool IsEnabled { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } [System.Runtime.CompilerServices.CompilerGeneratedAttribute]set { } }
     }
 }
+namespace Microsoft.AspNetCore.Hosting.Server.Abstractions
+{
+    public partial interface IHostContextContainer<TContext>
+    {
+        TContext HostContext { get; set; }
+    }
+}
 namespace Microsoft.AspNetCore.Hosting.Server.Features
 {
     public partial interface IServerAddressesFeature

src/Hosting/Server.Abstractions/src/IHostContextContainer.cs

@@ -0,0 +1,15 @@
+// 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.
+
+namespace Microsoft.AspNetCore.Hosting.Server.Abstractions
+{
+    /// <summary>
+    /// When implemented by a Server allows an <see cref="IHttpApplication{TContext}"/> to pool and reuse
+    /// its <typeparamref name="TContext"/> between requests.
+    /// </summary>
+    /// <typeparam name="TContext">The <see cref="IHttpApplication{TContext}"/> Host context</typeparam>
+    public interface IHostContextContainer<TContext>
+    {
+        TContext HostContext { get; set; }
+    }
+}

src/Hosting/TestHost/test/WebSocketClientTests.cs

@@ -2,11 +2,9 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Hosting;
-using Microsoft.AspNetCore.Http;
 using Xunit;
 
 namespace Microsoft.AspNetCore.TestHost.Tests
@@ -19,7 +17,9 @@ namespace Microsoft.AspNetCore.TestHost.Tests
         [InlineData("http://localhost:81/connect", "localhost:81")]
         public async Task ConnectAsync_ShouldSetRequestProperties(string requestUri, string expectedHost)
         {
-            HttpRequest capturedRequest = null;
+            string capturedScheme = null;
+            string capturedHost = null;
+            string capturedPath = null;
 
             using (var testServer = new TestServer(new WebHostBuilder()
                 .Configure(app =>
@@ -28,7 +28,9 @@ namespace Microsoft.AspNetCore.TestHost.Tests
                     {
                         if (ctx.Request.Path.StartsWithSegments("/connect"))
                         {
-                            capturedRequest = ctx.Request;
+                            capturedScheme = ctx.Request.Scheme;
+                            capturedHost = ctx.Request.Host.Value;
+                            capturedPath = ctx.Request.Path;
                         }
                         return Task.FromResult(0);
                     });
@@ -40,7 +42,7 @@ namespace Microsoft.AspNetCore.TestHost.Tests
                 {
                     await client.ConnectAsync(
                         uri: new Uri(requestUri),
-                        cancellationToken: default(CancellationToken));
+                        cancellationToken: default);
                 }
                 catch
                 {
@@ -48,9 +50,9 @@ namespace Microsoft.AspNetCore.TestHost.Tests
                 }
             }
 
-            Assert.Equal("http", capturedRequest.Scheme);
+            Assert.Equal("http", capturedScheme);
-            Assert.Equal(expectedHost, capturedRequest.Host.Value);
+            Assert.Equal(expectedHost, capturedHost);
-            Assert.Equal("/connect", capturedRequest.Path);
+            Assert.Equal("/connect", capturedPath);
         }
     }
 }

src/Http/Http.Features/src/FeatureReferences.cs

@@ -11,7 +11,7 @@ namespace Microsoft.AspNetCore.Http.Features
         public FeatureReferences(IFeatureCollection collection)
         {
             Collection = collection;
-            Cache = default(TCache);
+            Cache = default;
             Revision = collection.Revision;
         }
 
@@ -65,7 +65,7 @@ namespace Microsoft.AspNetCore.Http.Features
             Func<TState, TFeature> factory) where TFeature : class
         {
             var flush = false;
-            var revision = Collection.Revision;
+            var revision = Collection?.Revision ?? ContextDisposed();
             if (Revision != revision)
             {
                 // Clear cached value to force call to UpdateCached
@@ -83,7 +83,7 @@ namespace Microsoft.AspNetCore.Http.Features
             if (flush)
             {
                 // Collection detected as changed, clear cache
-                Cache = default(TCache);
+                Cache = default;
             }
 
             cached = Collection.Get<TFeature>();
@@ -108,5 +108,16 @@ namespace Microsoft.AspNetCore.Http.Features
 
         public TFeature Fetch<TFeature>(ref TFeature cached, Func<IFeatureCollection, TFeature> factory)
             where TFeature : class => Fetch(ref cached, Collection, factory);
+
+        private static int ContextDisposed()
+        {
+            ThrowContextDisposed();
+            return 0;
+        }
+
+        private static void ThrowContextDisposed()
+        {
+            throw new ObjectDisposedException(nameof(Collection), nameof(IFeatureCollection) + " has been disposed.");
+        }
     }
 }

src/Http/Http/ref/Microsoft.AspNetCore.Http.netcoreapp3.0.cs

@@ -54,12 +54,6 @@ namespace Microsoft.AspNetCore.Http
         public void Initialize(Microsoft.AspNetCore.Http.Features.IFeatureCollection features) { }
         public void Uninitialize() { }
     }
-    public partial class DefaultHttpContextFactory : Microsoft.AspNetCore.Http.IHttpContextFactory
-    {
-        public DefaultHttpContextFactory(System.IServiceProvider serviceProvider) { }
-        public Microsoft.AspNetCore.Http.HttpContext Create(Microsoft.AspNetCore.Http.Features.IFeatureCollection featureCollection) { throw null; }
-        public void Dispose(Microsoft.AspNetCore.Http.HttpContext httpContext) { }
-    }
     public partial class FormCollection : Microsoft.AspNetCore.Http.IFormCollection, System.Collections.Generic.IEnumerable<System.Collections.Generic.KeyValuePair<string, Microsoft.Extensions.Primitives.StringValues>>, System.Collections.IEnumerable
     {
         public static readonly Microsoft.AspNetCore.Http.FormCollection Empty;
@@ -164,10 +158,6 @@ namespace Microsoft.AspNetCore.Http
         public static void EnableBuffering(this Microsoft.AspNetCore.Http.HttpRequest request, int bufferThreshold, long bufferLimit) { }
         public static void EnableBuffering(this Microsoft.AspNetCore.Http.HttpRequest request, long bufferLimit) { }
     }
-    public partial interface IDefaultHttpContextContainer
-    {
-        Microsoft.AspNetCore.Http.DefaultHttpContext HttpContext { get; }
-    }
     public partial class MiddlewareFactory : Microsoft.AspNetCore.Http.IMiddlewareFactory
     {
         public MiddlewareFactory(System.IServiceProvider serviceProvider) { }

src/Http/Http/src/DefaultHttpContext.cs

@@ -90,7 +90,7 @@ namespace Microsoft.AspNetCore.Http
         private IHttpRequestIdentifierFeature RequestIdentifierFeature =>
             _features.Fetch(ref _features.Cache.RequestIdentifier, _newHttpRequestIdentifierFeature);
 
-        public override IFeatureCollection Features => _features.Collection;
+        public override IFeatureCollection Features => _features.Collection ?? ContextDisposed();
 
         public override HttpRequest Request => _request;
 
@@ -169,6 +169,17 @@ namespace Microsoft.AspNetCore.Http
             LifetimeFeature.Abort();
         }
 
+        private static IFeatureCollection ContextDisposed()
+        {
+            ThrowContextDisposed();
+            return null;
+        }
+
+        private static void ThrowContextDisposed()
+        {
+            throw new ObjectDisposedException(nameof(HttpContext), $"Request has finished and {nameof(HttpContext)} disposed.");
+        }
+
         struct FeatureInterfaces
         {
             public IItemsFeature Items;

src/Http/Http/src/HttpContextFactory.cs

@@ -54,7 +54,7 @@ namespace Microsoft.AspNetCore.Http
                 throw new ArgumentNullException(nameof(featureCollection));
             }
 
-            var httpContext = CreateHttpContext(featureCollection);
+            var httpContext = new DefaultHttpContext(featureCollection);
             if (_httpContextAccessor != null)
             {
                 _httpContextAccessor.HttpContext = httpContext;
@@ -66,16 +66,6 @@ namespace Microsoft.AspNetCore.Http
             return httpContext;
         }
 
-        private static DefaultHttpContext CreateHttpContext(IFeatureCollection featureCollection)
-        {
-            if (featureCollection is IDefaultHttpContextContainer container)
-            {
-                return container.HttpContext;
-            }
-
-            return new DefaultHttpContext(featureCollection);
-        }
-
         public void Dispose(HttpContext httpContext)
         {
             if (_httpContextAccessor != null)

src/Http/Http/src/IDefaultHttpContextContainer.cs

@@ -1,11 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Text;
-
-namespace Microsoft.AspNetCore.Http
-{
-    public interface IDefaultHttpContextContainer
-    {
-        DefaultHttpContext HttpContext { get; }
-    }
-}

src/Servers/Kestrel/Core/src/Internal/Http/Http1ConnectionOfT.cs

@@ -0,0 +1,14 @@
+// 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 Microsoft.AspNetCore.Hosting.Server.Abstractions;
+
+namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
+{
+    internal sealed class Http1Connection<TContext> : Http1Connection, IHostContextContainer<TContext>
+    {
+        public Http1Connection(HttpConnectionContext context) : base(context) { }
+
+        TContext IHostContextContainer<TContext>.HostContext { get; set; }
+    }
+}

src/Servers/Kestrel/Core/src/Internal/Http/HttpProtocol.cs

@@ -25,7 +25,7 @@ using Microsoft.Net.Http.Headers;
 
 namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
 {
-    internal abstract partial class HttpProtocol : IDefaultHttpContextContainer, IHttpResponseControl
+    internal abstract partial class HttpProtocol : IHttpResponseControl
     {
         private static readonly byte[] _bytesConnectionClose = Encoding.ASCII.GetBytes("\r\nConnection: close");
         private static readonly byte[] _bytesConnectionKeepAlive = Encoding.ASCII.GetBytes("\r\nConnection: keep-alive");
@@ -64,7 +64,6 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
         private long _responseBytesWritten;
 
         private readonly HttpConnectionContext _context;
-        private DefaultHttpContext _httpContext;
         private RouteValueDictionary _routeValues;
         private Endpoint _endpoint;
 
@@ -296,23 +295,6 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
 
         protected HttpResponseHeaders HttpResponseHeaders { get; } = new HttpResponseHeaders();
 
-        DefaultHttpContext IDefaultHttpContextContainer.HttpContext
-        {
-            get
-            {
-                if (_httpContext is null)
-                {
-                    _httpContext = new DefaultHttpContext(this);
-                }
-                else
-                {
-                    _httpContext.Initialize(this);
-                }
-
-                return _httpContext;
-            }
-        }
-
         public void InitializeBodyControl(MessageBody messageBody)
         {
             if (_bodyControl == null)
@@ -409,8 +391,6 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
 
             _responseBytesWritten = 0;
 
-            _httpContext?.Uninitialize();
-
             OnReset();
         }
 

src/Servers/Kestrel/Core/src/Internal/Http2/Http2StreamOfT.cs

@@ -1,11 +1,13 @@
-using System;
+// Copyright (c) .NET Foundation. All rights reserved.
-using System.Collections.Generic;
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
-using System.Text;
+
+
 using Microsoft.AspNetCore.Hosting.Server;
+using Microsoft.AspNetCore.Hosting.Server.Abstractions;
 
 namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2
 {
-    internal sealed class Http2Stream<TContext> : Http2Stream
+    internal sealed class Http2Stream<TContext> : Http2Stream, IHostContextContainer<TContext>
     {
         private readonly IHttpApplication<TContext> _application;
 
@@ -19,5 +21,8 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2
             // REVIEW: Should we store this in a field for easy debugging?
             _ = ProcessRequestsAsync(_application);
         }
+
+        // Pooled Host context
+        TContext IHostContextContainer<TContext>.HostContext { get; set; }
     }
 }

src/Servers/Kestrel/Core/src/Internal/HttpConnection.cs

@@ -55,7 +55,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal
                 {
                     case HttpProtocols.Http1:
                         // _http1Connection must be initialized before adding the connection to the connection manager
-                        requestProcessor = _http1Connection = new Http1Connection(_context);
+                        requestProcessor = _http1Connection = new Http1Connection<TContext>(_context);
                         _protocolSelectionState = ProtocolSelectionState.Selected;
                         break;
                     case HttpProtocols.Http2: