Make new StreamController().isPaused be true until the first listener arrives.

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 682 matching lines @@
   int get remotePort => _socket.remotePort;
 
   InternetAddress get address => _socket.address;
 
   String get remoteHost => _socket.remoteHost;
 
   bool get readEventsEnabled => _readEventsEnabled;
   void set readEventsEnabled(bool value) {
     if (value != _readEventsEnabled) {
       _readEventsEnabled = value;
-      if (_controller.hasListener && !_controller.isPaused) _resume();
+      if (!_controller.isPaused) _resume();
     }
   }
 
   bool get writeEventsEnabled => _writeEventsEnabled;
   void set writeEventsEnabled(bool value) {
     if (value != _writeEventsEnabled) {
       _writeEventsEnabled = value;
-      if (_controller.hasListener && !_controller.isPaused) _resume();
+      if (!_controller.isPaused) _resume();
     }
   }
 
   bool setOption(SocketOption option, bool enabled) =>
       _socket.setOption(option, enabled);
 
   _pause() {
     _socket.setListening(read: false, write: false);
   }
 
@@ skipping 343 matching lines @@
     if (_detachReady != null) {
       _detachReady.complete(null);
     } else {
       if (_raw != null) {
         _raw.shutdown(SocketDirection.SEND);
         _disableWriteEvent();
       }
     }
   }
 }