Dispose SocketAsyncEventArgs when we dispose the Socket (#2459)

src/Kestrel.Transport.Sockets/Internal/SocketConnection.cs

@@ -86,6 +86,8 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Transport.Sockets.Internal
 
                 // Dispose the socket(should noop if already called)
                 _socket.Dispose();
+                _receiver.Dispose();
+                _sender.Dispose();
             }
             catch (Exception ex)
             {

src/Kestrel.Transport.Sockets/Internal/SocketReceiver.cs

@@ -7,7 +7,7 @@ using System.Net.Sockets;
 
 namespace Microsoft.AspNetCore.Server.Kestrel.Transport.Sockets.Internal
 {
-    public class SocketReceiver
+    public class SocketReceiver : IDisposable
     {
         private readonly Socket _socket;
         private readonly SocketAsyncEventArgs _eventArgs = new SocketAsyncEventArgs();
@@ -37,5 +37,10 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Transport.Sockets.Internal
 
             return _awaitable;
         }
+
+        public void Dispose()
+        {
+            _eventArgs.Dispose();
+        }
     }
 }

src/Kestrel.Transport.Sockets/Internal/SocketSender.cs

@@ -11,7 +11,7 @@ using System.Runtime.InteropServices;
 
 namespace Microsoft.AspNetCore.Server.Kestrel.Transport.Sockets.Internal
 {
-    public class SocketSender
+    public class SocketSender : IDisposable
     {
         private readonly Socket _socket;
         private readonly SocketAsyncEventArgs _eventArgs = new SocketAsyncEventArgs();
@@ -98,5 +98,10 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Transport.Sockets.Internal
 
             return _bufferList;
         }
+
+        public void Dispose()
+        {
+            _eventArgs.Dispose();
+        }
     }
 }