nits

Author: benaadams

src/Microsoft.AspNetCore.Server.Kestrel/Internal/Http/PipelineExtensions.cs

@@ -2,13 +2,10 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using System.Diagnostics;
+using System.Buffers;
 using System.IO.Pipelines;
 using System.Runtime.CompilerServices;
-using System.Text;
-using System.Threading;
 using System.Threading.Tasks;
-using System.Buffers;
 
 namespace Microsoft.AspNetCore.Server.Kestrel.Internal.Http
 {