Remove usage of TaskCache (#1889)

* Remove usage of TaskCache

src/Microsoft.AspNetCore.Server.Kestrel.Core/Internal/Http/Frame.cs

@@ -12,15 +12,14 @@ using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Http.Features;
 using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Infrastructure;
 using Microsoft.AspNetCore.Server.Kestrel.Internal.System;
 using Microsoft.AspNetCore.Server.Kestrel.Internal.System.IO.Pipelines;
 using Microsoft.AspNetCore.Server.Kestrel.Internal.System.Text.Encodings.Web.Utf8;
 using Microsoft.AspNetCore.Server.Kestrel.Transport.Abstractions;
-using Microsoft.Extensions.Internal;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Primitives;
-using Microsoft.AspNetCore.Http.Features;
 
 // ReSharper disable AccessToModifiedClosure
 
@@ -526,7 +525,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
                 {
                     if (data.Count == 0)
                     {
-                        return TaskCache.CompletedTask;
+                        return Task.CompletedTask;
                     }
                     return WriteChunkedAsync(data, cancellationToken);
                 }
@@ -539,7 +538,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
             else
             {
                 HandleNonBodyResponseWrite();
-                return TaskCache.CompletedTask;
+                return Task.CompletedTask;
             }
         }
 
@@ -665,7 +664,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
         {
             if (HasResponseStarted)
             {
-                return TaskCache.CompletedTask;
+                return Task.CompletedTask;
             }
 
             if (_onStarting != null)
@@ -681,7 +680,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
             VerifyAndUpdateWrite(firstWriteByteCount);
             ProduceStart(appCompleted: false);
 
-            return TaskCache.CompletedTask;
+            return Task.CompletedTask;
         }
 
         private async Task InitializeResponseAwaited(int firstWriteByteCount)
@@ -716,7 +715,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
                 return ProduceEnd();
             }
 
-            return TaskCache.CompletedTask;
+            return Task.CompletedTask;
         }
 
         protected Task ProduceEnd()
@@ -727,7 +726,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
                 {
                     // We can no longer change the response, so we simply close the connection.
                     _requestProcessingStopping = true;
-                    return TaskCache.CompletedTask;
+                    return Task.CompletedTask;
                 }
 
                 // If the request was rejected, the error state has already been set by SetBadRequestState and
@@ -780,7 +779,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
                 Log.ConnectionHeadResponseBodyWrite(ConnectionId, _responseBytesWritten);
             }
 
-            return TaskCache.CompletedTask;
+            return Task.CompletedTask;
         }
 
         private async Task WriteAutoChunkSuffixAwaited()

src/Microsoft.AspNetCore.Server.Kestrel.Core/Internal/Http/FrameRequestStream.cs

@@ -3,12 +3,10 @@
 
 using System;
 using System.IO;
-using System.Runtime.ExceptionServices;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Infrastructure;
 using Microsoft.AspNetCore.Server.Kestrel.Transport.Abstractions;
-using Microsoft.Extensions.Internal;
 
 namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
 {
@@ -42,7 +40,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
         public override Task FlushAsync(CancellationToken cancellationToken)
         {
             // No-op.
-            return TaskCache.CompletedTask;
+            return Task.CompletedTask;
         }
 
         public override long Seek(long offset, SeekOrigin origin)

src/Microsoft.AspNetCore.Server.Kestrel.Core/Internal/Http/OutputProducer.cs

@@ -6,7 +6,6 @@ using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Infrastructure;
 using Microsoft.AspNetCore.Server.Kestrel.Internal.System.IO.Pipelines;
-using Microsoft.Extensions.Internal;
 
 namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
 {
@@ -110,7 +109,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
             {
                 if (_completed)
                 {
-                    return TaskCache.CompletedTask;
+                    return Task.CompletedTask;
                 }
 
                 writableBuffer = _pipe.Writer.Alloc(1);
@@ -143,7 +142,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
             if (awaitable.IsCompleted)
             {
                 // The flush task can't fail today
-                return TaskCache.CompletedTask;
+                return Task.CompletedTask;
             }
             return FlushAsyncAwaited(awaitable, cancellationToken);
         }

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

@@ -20,7 +20,6 @@
     <PackageReference Include="Microsoft.Net.Http.Headers" Version="$(AspNetCoreVersion)" />
     <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="$(AspNetCoreVersion)" />
     <PackageReference Include="Microsoft.Extensions.Options" Version="$(AspNetCoreVersion)" />
-    <PackageReference Include="Microsoft.Extensions.TaskCache.Sources" Version="$(AspNetCoreVersion)" PrivateAssets="All" />
     <PackageReference Include="System.Threading.Tasks.Extensions" Version="$(CoreFxVersion)" />
   </ItemGroup>
 

src/Microsoft.AspNetCore.Server.Kestrel.Https/Internal/ClosedStream.cs

@@ -5,12 +5,13 @@ using System;
 using System.IO;
 using System.Threading;
 using System.Threading.Tasks;
-using Microsoft.Extensions.Internal;
 
 namespace Microsoft.AspNetCore.Server.Kestrel.Https.Internal
 {
     internal class ClosedStream : Stream
     {
+        private static readonly Task<int> ZeroResultTask = Task.FromResult(result: 0);
+
         public override bool CanRead => true;
         public override bool CanSeek => false;
         public override bool CanWrite => false;
@@ -56,7 +57,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Https.Internal
 
         public override Task<int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
         {
-            return TaskCache<int>.DefaultCompletedTask;
+            return ZeroResultTask;
         }
 
         public override void Write(byte[] buffer, int offset, int count)

src/Microsoft.AspNetCore.Server.Kestrel.Https/Microsoft.AspNetCore.Server.Kestrel.Https.csproj

@@ -19,7 +19,6 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.AspNetCore.Http.Abstractions" Version="$(AspNetCoreVersion)" />
-    <PackageReference Include="Microsoft.Extensions.TaskCache.Sources" Version="$(AspNetCoreVersion)" PrivateAssets="All" />
   </ItemGroup>
 
   <ItemGroup>

src/Microsoft.AspNetCore.Server.Kestrel.Transport.Libuv/Microsoft.AspNetCore.Server.Kestrel.Transport.Libuv.csproj

@@ -17,7 +17,6 @@
     <PackageReference Include="Microsoft.AspNetCore.Hosting.Abstractions" Version="$(AspNetCoreVersion)" />
     <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="$(AspNetCoreVersion)" />
     <PackageReference Include="Microsoft.Extensions.Options" Version="$(AspNetCoreVersion)" />
-    <PackageReference Include="Microsoft.Extensions.TaskCache.Sources" Version="$(AspNetCoreVersion)" PrivateAssets="All" />
   </ItemGroup>
 
   <ItemGroup>

test/Microsoft.AspNetCore.Server.Kestrel.Core.Tests/FrameTests.cs

@@ -17,7 +17,6 @@ using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http;
 using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Infrastructure;
 using Microsoft.AspNetCore.Server.Kestrel.Internal.System.IO.Pipelines;
 using Microsoft.AspNetCore.Testing;
-using Microsoft.Extensions.Internal;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Primitives;
 using Moq;
@@ -240,7 +239,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
 
             // Act/Assert
             Assert.True(_frame.HasResponseStarted);
-            Assert.Throws<InvalidOperationException>(() => ((IHttpResponseFeature)_frame).OnStarting(_ => TaskCache.CompletedTask, null));
+            Assert.Throws<InvalidOperationException>(() => ((IHttpResponseFeature)_frame).OnStarting(_ => Task.CompletedTask, null));
         }
 
         [Fact]

test/Microsoft.AspNetCore.Server.Kestrel.Core.Tests/KestrelServerTests.cs

@@ -5,12 +5,12 @@ using System;
 using System.Linq;
 using System.Net;
 using System.Threading;
+using System.Threading.Tasks;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Hosting.Server;
 using Microsoft.AspNetCore.Hosting.Server.Features;
 using Microsoft.AspNetCore.Server.Kestrel.Transport.Abstractions;
 using Microsoft.AspNetCore.Testing;
-using Microsoft.Extensions.Internal;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
 using Moq;
@@ -161,7 +161,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
 
         private static void StartDummyApplication(IServer server)
         {
-            server.StartAsync(new DummyApplication(context => TaskCache.CompletedTask), CancellationToken.None).GetAwaiter().GetResult();
+            server.StartAsync(new DummyApplication(context => Task.CompletedTask), CancellationToken.None).GetAwaiter().GetResult();
         }
 
         private class MockTransportFactory : ITransportFactory

test/Microsoft.AspNetCore.Server.Kestrel.Core.Tests/MessageBodyTests.cs

@@ -9,14 +9,10 @@ using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Http;
-using Microsoft.AspNetCore.Server.Kestrel.Core.Internal;
 using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http;
 using Microsoft.AspNetCore.Testing;
-using Microsoft.Extensions.Internal;
-using Microsoft.Extensions.Logging;
 using Moq;
 using Xunit;
-using Xunit.Abstractions;
 using Xunit.Sdk;
 
 namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
@@ -398,7 +394,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
                     writeTcs.SetResult(buffer);
                     writeCount++;
                 })
-                .Returns(TaskCache.CompletedTask);
+                .Returns(Task.CompletedTask);
 
             using (var input = new TestInput())
             {

test/Microsoft.AspNetCore.Server.Kestrel.Core.Tests/TestHelpers/MockFrameControl.cs

@@ -5,7 +5,6 @@ using System;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http;
-using Microsoft.Extensions.Internal;
 
 namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests.TestHelpers
 {
@@ -13,7 +12,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests.TestHelpers
     {
         public Task FlushAsync(CancellationToken cancellationToken)
         {
-            return TaskCache.CompletedTask;
+            return Task.CompletedTask;
         }
 
         public void ProduceContinue()
@@ -22,7 +21,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests.TestHelpers
 
         public Task WriteAsync(ArraySegment<byte> data, CancellationToken cancellationToken)
         {
-            return TaskCache.CompletedTask;
+            return Task.CompletedTask;
         }
     }
 }

test/Microsoft.AspNetCore.Server.Kestrel.Core.Tests/TestInput.cs

@@ -2,17 +2,12 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using System.IO;
 using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http;
-using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Infrastructure;
 using Microsoft.AspNetCore.Server.Kestrel.Internal.System.IO.Pipelines;
-using Microsoft.AspNetCore.Server.Kestrel.Transport.Abstractions;
 using Microsoft.AspNetCore.Testing;
-using Microsoft.Extensions.Internal;
-using Moq;
 
 namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
 {
@@ -82,12 +77,12 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
 
         Task IFrameControl.WriteAsync(ArraySegment<byte> data, CancellationToken cancellationToken)
         {
-            return TaskCache.CompletedTask;
+            return Task.CompletedTask;
         }
 
         Task IFrameControl.FlushAsync(CancellationToken cancellationToken)
         {
-            return TaskCache.CompletedTask;
+            return Task.CompletedTask;
         }
 
         public void Dispose()

test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/BadHttpRequestTests.cs

@@ -9,7 +9,6 @@ using Microsoft.AspNetCore.Server.Kestrel.Core;
 using Microsoft.AspNetCore.Server.Kestrel.Core.Internal;
 using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Infrastructure;
 using Microsoft.AspNetCore.Testing;
-using Microsoft.Extensions.Internal;
 using Microsoft.Extensions.Logging;
 using Moq;
 using Xunit;
@@ -181,7 +180,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 .Setup(trace => trace.ConnectionBadRequest(It.IsAny<string>(), It.IsAny<BadHttpRequestException>()))
                 .Callback<string, BadHttpRequestException>((connectionId, exception) => loggedException = exception);
 
-            using (var server = new TestServer(context => TaskCache.CompletedTask, new TestServiceContext { Log = mockKestrelTrace.Object }))
+            using (var server = new TestServer(context => Task.CompletedTask, new TestServiceContext { Log = mockKestrelTrace.Object }))
             {
                 using (var connection = server.CreateConnection())
                 {

test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/ChunkedRequestTests.cs

@@ -10,7 +10,6 @@ using System.Threading.Tasks;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Server.Kestrel.Core;
 using Microsoft.AspNetCore.Testing;
-using Microsoft.Extensions.Internal;
 using Xunit;
 
 namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
@@ -538,7 +537,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
             var testContext = new TestServiceContext();
             using (var server = new TestServer(httpContext =>
             {
-                return TaskCache.CompletedTask;
+                return Task.CompletedTask;
             }, testContext, listenOptions))
             {
                 using (var connection = server.CreateConnection())

test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/DefaultHeaderTests.cs

@@ -3,7 +3,6 @@
 
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Testing;
-using Microsoft.Extensions.Internal;
 using Xunit;
 
 namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
@@ -18,7 +17,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 ServerOptions = { AddServerHeader = true }
             };
 
-            using (var server = new TestServer(ctx => TaskCache.CompletedTask, testContext))
+            using (var server = new TestServer(ctx => Task.CompletedTask, testContext))
             {
                 using (var connection = server.CreateConnection())
                 {

test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/HttpsConnectionAdapterTests.cs

@@ -17,7 +17,6 @@ using Microsoft.AspNetCore.Http.Features;
 using Microsoft.AspNetCore.Server.Kestrel.Core;
 using Microsoft.AspNetCore.Server.Kestrel.Https;
 using Microsoft.AspNetCore.Testing;
-using Microsoft.Extensions.Internal;
 using Xunit;
 
 namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
@@ -126,7 +125,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 }
             };
 
-            using (var server = new TestServer(context => TaskCache.CompletedTask, serviceContext, listenOptions))
+            using (var server = new TestServer(context => Task.CompletedTask, serviceContext, listenOptions))
             {
                 using (var client = new TcpClient())
                 {
@@ -256,7 +255,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 }
             };
 
-            using (var server = new TestServer(context => TaskCache.CompletedTask, serviceContext, listenOptions))
+            using (var server = new TestServer(context => Task.CompletedTask, serviceContext, listenOptions))
             {
                 using (var client = new TcpClient())
                 {
@@ -287,7 +286,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 }
             };
 
-            using (var server = new TestServer(context => TaskCache.CompletedTask, serviceContext, listenOptions))
+            using (var server = new TestServer(context => Task.CompletedTask, serviceContext, listenOptions))
             {
                 using (var client = new TcpClient())
                 {
@@ -316,7 +315,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 }
             };
 
-            using (var server = new TestServer(context => TaskCache.CompletedTask, serviceContext, listenOptions))
+            using (var server = new TestServer(context => Task.CompletedTask, serviceContext, listenOptions))
             {
                 using (var client = new TcpClient())
                 {

test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/RequestTests.cs

@@ -21,7 +21,6 @@ using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http;
 using Microsoft.AspNetCore.Server.Kestrel.Transport.Abstractions;
 using Microsoft.AspNetCore.Testing;
 using Microsoft.AspNetCore.Testing.xunit;
-using Microsoft.Extensions.Internal;
 using Microsoft.Extensions.Logging;
 using Moq;
 using Newtonsoft.Json;
@@ -291,7 +290,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 .Setup(factory => factory.CreateLogger(It.IsIn("Microsoft.AspNetCore.Server.Kestrel", "Microsoft.AspNetCore.Server.Kestrel.Transport.Libuv")))
                 .Returns(mockLogger.Object);
 
-            using (var server = new TestServer(context => TaskCache.CompletedTask, new TestServiceContext(mockLoggerFactory.Object)))
+            using (var server = new TestServer(context => Task.CompletedTask, new TestServiceContext(mockLoggerFactory.Object)))
             {
                 using (var connection = server.CreateConnection())
                 {
@@ -345,7 +344,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 .Setup(factory => factory.CreateLogger(It.IsIn("Microsoft.AspNetCore.Server.Kestrel", "Microsoft.AspNetCore.Server.Kestrel.Transport.Libuv")))
                 .Returns(mockLogger.Object);
 
-            using (var server = new TestServer(context => TaskCache.CompletedTask, new TestServiceContext(mockLoggerFactory.Object)))
+            using (var server = new TestServer(context => Task.CompletedTask, new TestServiceContext(mockLoggerFactory.Object)))
             {
                 using (var connection = server.CreateConnection())
                 {
@@ -1105,7 +1104,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                     Assert.Same(originalRequestHeaders, requestFeature.Headers);
                 }
 
-                return TaskCache.CompletedTask;
+                return Task.CompletedTask;
             }, testContext, listenOptions))
             {
                 using (var connection = server.CreateConnection())

test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/ResponseTests.cs

@@ -21,7 +21,6 @@ using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http;
 using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Infrastructure;
 using Microsoft.AspNetCore.Testing;
 using Microsoft.Extensions.DependencyInjection;
-using Microsoft.Extensions.Internal;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Primitives;
 using Moq;
@@ -182,7 +181,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                     {
                         await context.Response.WriteAsync("hello, world");
                         await context.Response.Body.FlushAsync();
-                        ex = Assert.Throws<InvalidOperationException>(() => context.Response.OnStarting(_ => TaskCache.CompletedTask, null));
+                        ex = Assert.Throws<InvalidOperationException>(() => context.Response.OnStarting(_ => Task.CompletedTask, null));
                     });
                 });
 
@@ -220,7 +219,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 context =>
                 {
                     context.Abort();
-                    return TaskCache.CompletedTask;
+                    return Task.CompletedTask;
                 },
                 expectedClientStatusCode: null,
                 expectedServerStatusCode: 0);
@@ -245,7 +244,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
             return ResponseStatusCodeSetBeforeHttpContextDispose(
                 context =>
                 {
-                    return TaskCache.CompletedTask;
+                    return Task.CompletedTask;
                 },
                 expectedClientStatusCode: null,
                 expectedServerStatusCode: HttpStatusCode.BadRequest,
@@ -421,7 +420,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
             using (var server = new TestServer(httpContext =>
             {
                 httpContext.Response.StatusCode = statusCode;
-                return TaskCache.CompletedTask;
+                return Task.CompletedTask;
             }))
             {
                 using (var connection = server.CreateConnection())
@@ -445,7 +444,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
         {
             using (var server = new TestServer(httpContext =>
             {
-                return TaskCache.CompletedTask;
+                return Task.CompletedTask;
             }))
             {
                 using (var connection = server.CreateConnection())
@@ -516,7 +515,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 httpContext.Response.ContentLength = 11;
                 httpContext.Response.Body.Write(Encoding.ASCII.GetBytes("hello,"), 0, 6);
                 httpContext.Response.Body.Write(Encoding.ASCII.GetBytes(" world"), 0, 6);
-                return TaskCache.CompletedTask;
+                return Task.CompletedTask;
             }, serviceContext))
             {
                 using (var connection = server.CreateConnection())
@@ -592,7 +591,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 var response = Encoding.ASCII.GetBytes("hello, world");
                 httpContext.Response.ContentLength = 5;
                 httpContext.Response.Body.Write(response, 0, response.Length);
-                return TaskCache.CompletedTask;
+                return Task.CompletedTask;
             }, serviceContext))
             {
                 using (var connection = server.CreateConnection())
@@ -764,7 +763,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
             using (var server = new TestServer(httpContext =>
             {
                 httpContext.Response.ContentLength = 5;
-                return TaskCache.CompletedTask;
+                return Task.CompletedTask;
             }, serviceContext))
             {
                 using (var connection = server.CreateConnection())
@@ -912,7 +911,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
             using (var server = new TestServer(httpContext =>
             {
                 httpContext.Response.ContentLength = 42;
-                return TaskCache.CompletedTask;
+                return Task.CompletedTask;
             }))
             {
                 using (var connection = server.CreateConnection())
@@ -973,7 +972,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 httpContext.Response.ContentLength = 12;
                 httpContext.Response.Body.Write(Encoding.ASCII.GetBytes("hello, world"), 0, 12);
                 flushed.Wait();
-                return TaskCache.CompletedTask;
+                return Task.CompletedTask;
             }))
             {
                 using (var connection = server.CreateConnection())
@@ -1255,7 +1254,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     // Change response to chunked
                     httpContext.Response.ContentLength = null;
-                    return TaskCache.CompletedTask;
+                    return Task.CompletedTask;
                 });
 
                 var response = Encoding.ASCII.GetBytes("hello, world");
@@ -1263,7 +1262,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
 
                 // If OnStarting is not run before verifying writes, an error response will be sent.
                 httpContext.Response.Body.Write(response, 0, response.Length);
-                return TaskCache.CompletedTask;
+                return Task.CompletedTask;
             }))
             {
                 using (var connection = server.CreateConnection())
@@ -1296,7 +1295,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     // Change response to chunked
                     httpContext.Response.ContentLength = null;
-                    return TaskCache.CompletedTask;
+                    return Task.CompletedTask;
                 });
 
                 var response = Encoding.ASCII.GetBytes("hello, world");
@@ -1305,7 +1304,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 // If OnStarting is not run before verifying writes, an error response will be sent.
                 httpContext.Response.Body.Write(response, 0, response.Length / 2);
                 httpContext.Response.Body.Write(response, response.Length / 2, response.Length - response.Length / 2);
-                return TaskCache.CompletedTask;
+                return Task.CompletedTask;
             }))
             {
                 using (var connection = server.CreateConnection())
@@ -1340,7 +1339,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     // Change response to chunked
                     httpContext.Response.ContentLength = null;
-                    return TaskCache.CompletedTask;
+                    return Task.CompletedTask;
                 });
 
                 var response = Encoding.ASCII.GetBytes("hello, world");
@@ -1380,7 +1379,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     // Change response to chunked
                     httpContext.Response.ContentLength = null;
-                    return TaskCache.CompletedTask;
+                    return Task.CompletedTask;
                 });
 
                 var response = Encoding.ASCII.GetBytes("hello, world");
@@ -1454,7 +1453,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
         [Fact]
         public async Task WhenResponseNotStartedResponseEndedAfterConsumingRequestBody()
         {
-            using (var server = new TestServer(httpContext => TaskCache.CompletedTask))
+            using (var server = new TestServer(httpContext => Task.CompletedTask))
             {
                 using (var connection = server.CreateConnection())
                 {
@@ -1822,7 +1821,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 response.OnStarting(_ =>
                 {
                     onStartingCalled = true;
-                    return TaskCache.CompletedTask;
+                    return Task.CompletedTask;
                 }, null);
 
                 // Anything added to the ResponseHeaders dictionary is ignored
@@ -2166,7 +2165,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
             using (var server = new TestServer(httpContext =>
             {
                 httpContext.Abort();
-                return TaskCache.CompletedTask;
+                return Task.CompletedTask;
             }, testContext, listenOptions))
             {
                 using (var connection = server.CreateConnection())
@@ -2205,7 +2204,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                     Assert.Same(originalResponseHeaders, responseFeature.Headers);
                 }
 
-                return TaskCache.CompletedTask;
+                return Task.CompletedTask;
             }, testContext, listenOptions))
             {
                 using (var connection = server.CreateConnection())
@@ -2249,12 +2248,12 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     callOrder.Push(1);
                     onStartingTcs.SetResult(null);
-                    return TaskCache.CompletedTask;
+                    return Task.CompletedTask;
                 }, null);
                 context.Response.OnStarting(_ =>
                 {
                     callOrder.Push(2);
-                    return TaskCache.CompletedTask;
+                    return Task.CompletedTask;
                 }, null);
 
                 context.Response.ContentLength = response.Length;
@@ -2301,12 +2300,12 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                 {
                     callOrder.Push(1);
                     onCompletedTcs.SetResult(null);
-                    return TaskCache.CompletedTask;
+                    return Task.CompletedTask;
                 }, null);
                 context.Response.OnCompleted(_ =>
                 {
                     callOrder.Push(2);
-                    return TaskCache.CompletedTask;
+                    return Task.CompletedTask;
                 }, null);
 
                 context.Response.ContentLength = response.Length;

test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/UpgradeTests.cs

@@ -9,7 +9,6 @@ using Microsoft.AspNetCore.Server.Kestrel.Core;
 using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Infrastructure;
 using Microsoft.AspNetCore.Server.Kestrel.Tests;
 using Microsoft.AspNetCore.Testing;
-using Microsoft.Extensions.Internal;
 using Xunit;
 using Xunit.Abstractions;
 
@@ -154,7 +153,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
         [Fact]
         public async Task RejectsRequestWithContentLengthAndUpgrade()
         {
-            using (var server = new TestServer(context => TaskCache.CompletedTask))
+            using (var server = new TestServer(context => Task.CompletedTask))
             using (var connection = server.CreateConnection())
             {
                 await connection.Send("POST / HTTP/1.1",
@@ -177,7 +176,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
         [Fact]
         public async Task AcceptsRequestWithNoContentLengthAndUpgrade()
         {
-            using (var server = new TestServer(context => TaskCache.CompletedTask))
+            using (var server = new TestServer(context => Task.CompletedTask))
             {
                 using (var connection = server.CreateConnection())
                 {
@@ -201,7 +200,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
         [Fact]
         public async Task RejectsRequestWithChunkedEncodingAndUpgrade()
         {
-            using (var server = new TestServer(context => TaskCache.CompletedTask))
+            using (var server = new TestServer(context => Task.CompletedTask))
             using (var connection = server.CreateConnection())
             {
                 await connection.Send("POST / HTTP/1.1",

test/shared/TestApp.cs

@@ -4,7 +4,6 @@
 using System.IO;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Http;
-using Microsoft.Extensions.Internal;
 
 namespace Microsoft.AspNetCore.Testing
 {
@@ -43,7 +42,7 @@ namespace Microsoft.AspNetCore.Testing
 
         public static Task EmptyApp(HttpContext httpContext)
         {
-            return TaskCache.CompletedTask;
+            return Task.CompletedTask;
         }
     }
 }