Remove extra await/state machine in FlushAsync (#7646)

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

@@ -574,7 +574,6 @@ namespace System.IO.Pipelines
         public override System.IAsyncResult BeginWrite(byte[] buffer, int offset, int count, System.AsyncCallback callback, object state) { throw null; }
         public override void EndWrite(System.IAsyncResult asyncResult) { }
         public override void Flush() { }
-        [System.Diagnostics.DebuggerStepThroughAttribute]
         public override System.Threading.Tasks.Task FlushAsync(System.Threading.CancellationToken cancellationToken) { throw null; }
         public override int Read(byte[] buffer, int offset, int count) { throw null; }
         public override System.Threading.Tasks.Task<int> ReadAsync(byte[] buffer, int offset, int count, System.Threading.CancellationToken cancellationToken) { throw null; }

src/Http/Http/src/Microsoft.AspNetCore.Http.csproj

@@ -12,6 +12,7 @@
 
   <ItemGroup>
     <Compile Include="$(SharedSourceRoot)CopyOnWriteDictionary\*.cs" />
+    <Compile Include="$(SharedSourceRoot)ValueTaskExtensions\**\*.cs" />
   </ItemGroup>
 
   <ItemGroup>

src/Http/Http/src/WriteOnlyPipeStream.cs

@@ -3,6 +3,7 @@
 
 using System.Threading;
 using System.Threading.Tasks;
+using Microsoft.AspNetCore.Internal;
 
 namespace System.IO.Pipelines
 {
@@ -76,14 +77,14 @@ namespace System.IO.Pipelines
             {
                 ThrowHelper.ThrowInvalidOperationException_SynchronousFlushesDisallowed();
             }
-            
+
             FlushAsync(default).GetAwaiter().GetResult();
         }
 
         /// <inheritdoc />
-        public override async Task FlushAsync(CancellationToken cancellationToken)
+        public override Task FlushAsync(CancellationToken cancellationToken)
         {
-            await InnerPipeWriter.FlushAsync(cancellationToken);
+            return InnerPipeWriter.FlushAsync(cancellationToken).GetAsTask();
         }
 
         /// <inheritdoc />
@@ -162,16 +163,7 @@ namespace System.IO.Pipelines
 
         private Task WriteAsyncInternal(ReadOnlyMemory<byte> source, CancellationToken cancellationToken = default)
         {
-            var task = InnerPipeWriter.WriteAsync(source, cancellationToken);
-
-            if (task.IsCompletedSuccessfully)
-            {
-                // Most ValueTask implementations reset in GetResult, so call it before returning completed task
-                task.GetAwaiter().GetResult();
-                return Task.CompletedTask;
-            }
-
-            return task.AsTask();
+            return InnerPipeWriter.WriteAsync(source, cancellationToken).GetAsTask();
         }
     }
 }

src/Servers/Kestrel/Core/src/Internal/Http/Http1OutputProducer.cs

@@ -8,6 +8,7 @@ using System.IO.Pipelines;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Connections;
+using Microsoft.AspNetCore.Internal;
 using Microsoft.AspNetCore.Server.Kestrel.Core.Features;
 using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Infrastructure;
 

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

@@ -16,6 +16,7 @@ using Microsoft.AspNetCore.Connections;
 using Microsoft.AspNetCore.Hosting.Server;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Http.Features;
+using Microsoft.AspNetCore.Internal;
 using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Infrastructure;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Primitives;

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

@@ -1,27 +0,0 @@
-// 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.IO.Pipelines;
-using System.Runtime.CompilerServices;
-using System.Threading.Tasks;
-
-namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
-{
-    internal static class ValueTaskExtensions
-    {
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public static Task GetAsTask(this in ValueTask<FlushResult> valueTask)
-        {
-            if (valueTask.IsCompletedSuccessfully)
-            {
-                // Signal consumption to the IValueTaskSource
-                valueTask.GetAwaiter().GetResult();
-                return Task.CompletedTask;
-            }
-            else
-            {
-                return valueTask.AsTask();
-            }
-        }
-    }
-}

src/Servers/Kestrel/Core/src/Internal/Http2/Http2OutputProducer.cs

@@ -8,6 +8,7 @@ using System.IO.Pipelines;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Connections;
+using Microsoft.AspNetCore.Internal;
 using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http;
 using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2.FlowControl;
 using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Infrastructure;

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

@@ -12,6 +12,7 @@
 
   <ItemGroup>
     <Compile Include="$(SharedSourceRoot)CertificateGeneration\**\*.cs" />
+    <Compile Include="$(SharedSourceRoot)ValueTaskExtensions\**\*.cs" />
   </ItemGroup>
 
   <ItemGroup>

src/SignalR/clients/csharp/Client.Core/src/Microsoft.AspNetCore.SignalR.Client.Core.csproj

@@ -13,7 +13,10 @@
     <Compile Include="$(SignalRSharedSourceRoot)PipeWriterStream.cs" Link="PipeWriterStream.cs" />
     <Compile Include="$(SignalRSharedSourceRoot)ReflectionHelper.cs" Link="ReflectionHelper.cs" />
     <Compile Include="$(SignalRSharedSourceRoot)TimerAwaitable.cs" Link="Internal\TimerAwaitable.cs" />
-    <Compile Include="$(SignalRSharedSourceRoot)ValueTaskExtensions.cs" Link="Internal\ValueTaskExtensions.cs" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Compile Include="$(SharedSourceRoot)ValueTaskExtensions\**\*.cs" />
   </ItemGroup>
 
   <ItemGroup>

src/SignalR/common/Http.Connections/src/Microsoft.AspNetCore.Http.Connections.csproj

@@ -14,12 +14,12 @@
     <Compile Include="$(SignalRSharedSourceRoot)WebSocketExtensions.cs" Link="WebSocketExtensions.cs" />
     <Compile Include="$(SignalRSharedSourceRoot)StreamExtensions.cs" Link="StreamExtensions.cs" />
     <Compile Include="$(SignalRSharedSourceRoot)DuplexPipe.cs" Link="DuplexPipe.cs" />
-    <Compile Include="$(SignalRSharedSourceRoot)ValueTaskExtensions.cs" Link="ValueTaskExtensions.cs" />
   </ItemGroup>
 
   <ItemGroup>
     <Compile Include="$(SharedSourceRoot)SecurityHelper\**\*.cs" />
     <Compile Include="$(SharedSourceRoot)WebEncoders\**\*.cs" />
+    <Compile Include="$(SharedSourceRoot)ValueTaskExtensions\**\*.cs" />
   </ItemGroup>
 
   <ItemGroup>