Reduce delegate allocation

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

@@ -3,10 +3,10 @@
 
 using System;
 using System.Collections.Generic;
+using System.IO;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.Extensions.Primitives;
-using System.IO;
 
 namespace Microsoft.AspNet.Server.Kestrel.Http
 {
@@ -94,7 +94,7 @@ public static bool TryGet(IDictionary<string, StringValues> headers, string name
                 value = values[0];
                 return true;
             }
-            value = String.Join(",", values);
+            value = string.Join(",", values.ToArray());
             return true;
         }
 

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

@@ -25,7 +25,7 @@ protected override UvStreamHandle CreateListenSocket()
             var socket = new UvPipeHandle(Log);
             socket.Init(Thread.Loop, false);
             socket.Bind(ServerAddress.UnixPipePath);
-            socket.Listen(Constants.ListenBacklog, ConnectionCallback, this);
+            socket.Listen(Constants.ListenBacklog, (stream, status, error, state) => ConnectionCallback(stream, status, error, state), this);
             return socket;
         }
 

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

@@ -25,7 +25,7 @@ protected override UvStreamHandle CreateListenSocket()
             var socket = new UvPipeHandle(Log);
             socket.Init(Thread.Loop, false);
             socket.Bind(ServerAddress.UnixPipePath);
-            socket.Listen(Constants.ListenBacklog, ConnectionCallback, this);
+            socket.Listen(Constants.ListenBacklog, (stream, status, error, state) => ConnectionCallback(stream, status, error, state), this);
             return socket;
         }
 

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

@@ -25,7 +25,7 @@ protected override UvStreamHandle CreateListenSocket()
             socket.Init(Thread.Loop, Thread.QueueCloseHandle);
             socket.NoDelay(NoDelay);
             socket.Bind(ServerAddress);
-            socket.Listen(Constants.ListenBacklog, ConnectionCallback, this);
+            socket.Listen(Constants.ListenBacklog, (stream, status, error, state) => ConnectionCallback(stream, status, error, state), this);
             return socket;
         }
 

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

@@ -27,7 +27,7 @@ protected override UvStreamHandle CreateListenSocket()
             socket.Init(Thread.Loop, Thread.QueueCloseHandle);
             socket.NoDelay(NoDelay);
             socket.Bind(ServerAddress);
-            socket.Listen(Constants.ListenBacklog, ConnectionCallback, this);
+            socket.Listen(Constants.ListenBacklog, (stream, status, error, state) => ConnectionCallback(stream, status, error, state), this);
             return socket;
         }
 

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

@@ -8,7 +8,7 @@ namespace Microsoft.AspNet.Server.Kestrel.Networking
 {
     public class UvAsyncHandle : UvHandle
     {
-        private static Libuv.uv_async_cb _uv_async_cb = AsyncCb;
+        private static Libuv.uv_async_cb _uv_async_cb = (handle) => AsyncCb(handle);
         private Action _callback;
 
         public UvAsyncHandle(IKestrelTrace logger) : base(logger)

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

@@ -12,7 +12,7 @@ namespace Microsoft.AspNet.Server.Kestrel.Networking
     /// </summary>
     public class UvConnectRequest : UvRequest
     {
-        private readonly static Libuv.uv_connect_cb _uv_connect_cb = UvConnectCb;
+        private readonly static Libuv.uv_connect_cb _uv_connect_cb = (req, status) => UvConnectCb(req, status);
 
         private Action<UvConnectRequest, int, Exception, object> _callback;
         private object _state;

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

@@ -9,7 +9,7 @@ namespace Microsoft.AspNet.Server.Kestrel.Networking
 {
     public abstract class UvHandle : UvMemory
     {
-        private static Libuv.uv_close_cb _destroyMemory = DestroyMemory;
+        private static Libuv.uv_close_cb _destroyMemory = (handle) => DestroyMemory(handle);
         private Action<Action<IntPtr>, IntPtr> _queueCloseHandle;
 
         protected UvHandle(IKestrelTrace logger) : base (logger)

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

@@ -10,9 +10,10 @@ namespace Microsoft.AspNet.Server.Kestrel.Networking
 {
     public abstract class UvStreamHandle : UvHandle
     {
-        private readonly static Libuv.uv_connection_cb _uv_connection_cb = UvConnectionCb;
-        private readonly static Libuv.uv_alloc_cb _uv_alloc_cb = UvAllocCb;
-        private readonly static Libuv.uv_read_cb _uv_read_cb = UvReadCb;
+        private readonly static Libuv.uv_connection_cb _uv_connection_cb = (handle, status) => UvConnectionCb(handle, status);
+        // Ref and out lamda params must be explicitly typed
+        private readonly static Libuv.uv_alloc_cb _uv_alloc_cb = (IntPtr handle, int suggested_size, out Libuv.uv_buf_t buf) => UvAllocCb(handle, suggested_size, out buf);
+        private readonly static Libuv.uv_read_cb _uv_read_cb = (IntPtr handle, int status, ref Libuv.uv_buf_t buf) => UvReadCb(handle, status, ref buf);
 
         public Action<UvStreamHandle, int, Exception, object> _listenCallback;
         public object _listenState;