Use ArrayPool.Shared for StreamCopyOperation

src/Microsoft.AspNet.StaticFiles/StreamCopyOperation.cs

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.Buffers;
 using System.Diagnostics;
 using System.IO;
 using System.Threading;
@@ -12,13 +13,15 @@ namespace Microsoft.AspNet.StaticFiles
     // FYI: In most cases the source will be a FileStream and the destination will be to the network.
     internal static class StreamCopyOperation
     {
-        private const int DefaultBufferSize = 1024 * 16;
+        private const int DefaultBufferSize = 4096;
 
         internal static async Task CopyToAsync(Stream source, Stream destination, long? length, CancellationToken cancel)
         {
             long? bytesRemaining = length;
-            byte[] buffer = new byte[DefaultBufferSize];
 
+            var buffer = ArrayPool<byte>.Shared.Rent(DefaultBufferSize);
+            try
+            {
                 Debug.Assert(source != null);
                 Debug.Assert(destination != null);
                 Debug.Assert(!bytesRemaining.HasValue || bytesRemaining.Value >= 0);
@@ -57,5 +60,10 @@ namespace Microsoft.AspNet.StaticFiles
                     await destination.WriteAsync(buffer, 0, count, cancel);
                 }
             }
+            finally
+            {
+                ArrayPool<byte>.Shared.Return(buffer);
+            }
+        }
     }
 }

src/Microsoft.AspNet.StaticFiles/project.json

@@ -14,7 +14,8 @@
     "Microsoft.AspNet.FileProviders.Abstractions": "1.0.0-*",
     "Microsoft.AspNet.Hosting.Abstractions": "1.0.0-*",
     "Microsoft.Extensions.Logging.Abstractions": "1.0.0-*",
-    "Microsoft.Extensions.WebEncoders": "1.0.0-*"
+    "Microsoft.Extensions.WebEncoders": "1.0.0-*",
+    "System.Buffers": "4.0.0-*"
   },
   "frameworks": {
     "net451": {},