Use TaskCache class from Microsoft.Extensions.TaskCache.Sources

src/Microsoft.AspNetCore.ResponseCaching/ResponseCachingMiddleware.cs

@@ -6,6 +6,7 @@ using System.Text;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.Internal;
 using Microsoft.Extensions.ObjectPool;
 using Microsoft.Extensions.Options;
 
@@ -16,7 +17,7 @@ namespace Microsoft.AspNetCore.ResponseCaching
         private static readonly Func<object, Task> OnStartingCallback = state =>
         {
             ((ResponseCachingContext)state).OnResponseStarting();
-            return Task.FromResult(0);
+            return TaskCache.CompletedTask;
         };
 
         private readonly RequestDelegate _next;

src/Microsoft.AspNetCore.ResponseCaching/project.json

@@ -23,7 +23,11 @@
   "dependencies": {
     "Microsoft.AspNetCore.Http": "1.1.0-*",
     "Microsoft.AspNetCore.Http.Extensions": "1.1.0-*",
-    "Microsoft.Extensions.Caching.Memory": "1.1.0-*"
+    "Microsoft.Extensions.Caching.Memory": "1.1.0-*",
+    "Microsoft.Extensions.TaskCache.Sources": {
+      "version": "1.1.0-*",
+      "type": "build"
+    }
   },
   "frameworks": {
     "net451": {},