Add IOSink:flush().

runtime/bin/socket_patch.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 patch class RawServerSocket {
   /* patch */ static Future<RawServerSocket> bind(address,
                                                   int port,
                                                   {int backlog: 0,
                                                    bool v6Only: false}) {
     return _RawServerSocket.bind(address, port, backlog, v6Only);
@@ skipping 1073 matching lines @@
   void writeCharCode(int charCode) => _sink.writeCharCode(charCode);
 
   void writeAll(Iterable objects, [sep = ""]) => _sink.writeAll(objects, sep);
 
   void add(List<int> bytes) => _sink.add(bytes);
 
   Future<Socket> addStream(Stream<List<int>> stream) {
     return _sink.addStream(stream);
   }
 
+  Future<Socket> flush() => _sink.flush();
+
   Future<Socket> close() => _sink.close();
 
   Future<Socket> get done => _sink.done;
 
   void destroy() {
     // Destroy can always be called to get rid of a socket.
     if (_raw == null) return;
     _consumer.stop();
     _closeRawSocket();
     _controllerClosed = true;
@@ skipping 110 matching lines @@
     if (_detachReady != null) {
       _detachReady.complete(null);
     } else {
       if (_raw != null) {
         _raw.shutdown(SocketDirection.SEND);
         _disableWriteEvent();
       }
     }
   }
 }