Use TaskCache class from Microsoft.Extensions.TaskCache.Sources (#254)

Instead of Task.FromResult(0)

src/Microsoft.AspNetCore.Server.WebListener/AuthenticationHandler.cs

@@ -26,6 +26,7 @@ using System.Collections.Generic;
 using System.Security.Claims;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Http.Features.Authentication;
+using Microsoft.Extensions.Internal;
 using Microsoft.Net.Http.Server;
 
 namespace Microsoft.AspNetCore.Server.WebListener
@@ -63,7 +64,7 @@ namespace Microsoft.AspNetCore.Server.WebListener
                     }
                 }
             }
-            return Task.FromResult(0);
+            return TaskCache.CompletedTask;
         }
 
         public Task ChallengeAsync(ChallengeContext context)
@@ -108,7 +109,7 @@ namespace Microsoft.AspNetCore.Server.WebListener
             }
             // A challenge was issued, it overrides any pre-set auth types.
             _requestContext.Response.AuthenticationChallenges = _customChallenges;
-            return Task.FromResult(0);
+            return TaskCache.CompletedTask;
         }
 
         public void GetDescriptions(DescribeSchemesContext context)
@@ -123,13 +124,13 @@ namespace Microsoft.AspNetCore.Server.WebListener
         public Task SignInAsync(SignInContext context)
         {
             // Not supported. AuthenticationManager will throw if !Accepted.
-            return Task.FromResult(0);
+            return TaskCache.CompletedTask;
         }
 
         public Task SignOutAsync(SignOutContext context)
         {
             // Not supported. AuthenticationManager will throw if !Accepted.
-            return Task.FromResult(0);
+            return TaskCache.CompletedTask;
         }
 
         private IDictionary<string, object> GetDescription(string authenticationScheme)

src/Microsoft.AspNetCore.Server.WebListener/FeatureContext.cs

@@ -28,6 +28,7 @@ using System.Threading.Tasks;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Http.Features;
 using Microsoft.AspNetCore.Http.Features.Authentication;
+using Microsoft.Extensions.Internal;
 using Microsoft.Net.Http.Headers;
 using Microsoft.Net.Http.Server;
 
@@ -590,7 +591,7 @@ namespace Microsoft.AspNetCore.Server.WebListener
         {
             if (_completed)
             {
-                return Helpers.CompletedTask;
+                return TaskCache.CompletedTask;
             }
             _completed = true;
             return NotifyOnCompletedAsync();

src/Microsoft.AspNetCore.Server.WebListener/Helpers.cs

@@ -28,8 +28,6 @@ namespace Microsoft.AspNetCore.Server.WebListener
 {
     internal static class Helpers
     {
-        internal static Task CompletedTask { get; } = Task.FromResult(0);
-
         internal static ConfiguredTaskAwaitable SupressContext(this Task task)
         {
             return task.ConfigureAwait(continueOnCapturedContext: false);

src/Microsoft.AspNetCore.Server.WebListener/project.json

@@ -4,7 +4,11 @@
   "dependencies": {
     "Microsoft.AspNetCore.Hosting": "1.1.0-*",
     "Microsoft.Net.Http.Headers": "1.1.0-*",
-    "Microsoft.Net.Http.Server": "0.2.0-*"
+    "Microsoft.Net.Http.Server": "0.2.0-*",
+    "Microsoft.Extensions.TaskCache.Sources": {
+      "version": "1.1.0-*",
+      "type": "build"
+    }
   },
   "buildOptions": {
     "allowUnsafe": true,