Removing unnecessary using statements

src/Microsoft.AspNet.Server.Kestrel/Http/Connection.cs

@@ -2,9 +2,6 @@
 // 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.Net.Sockets;
-using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.AspNet.Server.Kestrel.Networking;
 

src/Microsoft.AspNet.Server.Kestrel/Http/Frame.cs

@@ -4,9 +4,7 @@
 using Microsoft.AspNet.HttpFeature;
 using System;
 using System.Collections.Generic;
-using System.Globalization;
 using System.Linq;
-using System.Net;
 using System.Text;
 using System.Threading.Tasks;
 

src/Microsoft.AspNet.Server.Kestrel/Http/Listener.cs

@@ -4,7 +4,6 @@
 using Microsoft.AspNet.Server.Kestrel.Networking;
 using System;
 using System.Net;
-using System.Text;
 using System.Threading.Tasks;
 
 namespace Microsoft.AspNet.Server.Kestrel.Http

src/Microsoft.AspNet.Server.Kestrel/Http/MemoryPool.cs

@@ -3,7 +3,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Net.Sockets;
 
 namespace Microsoft.AspNet.Server.Kestrel.Http
 {

src/Microsoft.AspNet.Server.Kestrel/Http/MessageBody.cs

@@ -3,7 +3,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Threading;
 
 namespace Microsoft.AspNet.Server.Kestrel.Http
 {

src/Microsoft.AspNet.Server.Kestrel/Http/SocketOutput.cs

@@ -3,9 +3,6 @@
 
 using Microsoft.AspNet.Server.Kestrel.Networking;
 using System;
-using System.Collections.Generic;
-using System.Diagnostics;
-using System.Net.Sockets;
 using System.Runtime.InteropServices;
 
 namespace Microsoft.AspNet.Server.Kestrel.Http

src/Microsoft.AspNet.Server.Kestrel/KestrelEngine.cs

@@ -3,7 +3,6 @@
 
 using System;
 using Microsoft.AspNet.Server.Kestrel.Networking;
-using System.Threading;
 using System.Collections.Generic;
 using System.Threading.Tasks;
 using Microsoft.AspNet.Server.Kestrel.Http;

src/Microsoft.AspNet.Server.Kestrel/Networking/UcAsyncHandle.cs

@@ -2,7 +2,6 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using System.Runtime.InteropServices;
 
 namespace Microsoft.AspNet.Server.Kestrel.Networking
 {

src/Microsoft.AspNet.Server.Kestrel/Networking/UvStreamHandle.cs

@@ -2,7 +2,6 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using System.Runtime.InteropServices;
 
 namespace Microsoft.AspNet.Server.Kestrel.Networking
 {