anchor.diff:    bool isClosing = false;
     bool isClosedRead = false;
     bool isClosedWrite = false;
  -  Completer closeCompleter = new Completer();
  +  Completer closeCompleter = new Completer.sync();
   
     // Handlers and receive port for socket events from the event handler.
     int eventMask = 0;
  
positive.code:         onCancel: _onSubscriptionStateChange,
          onPause: _onPauseStateChange,
          onResume: _onPauseStateChange);
      _socket.closeFuture.then((_) => _controller.close());
      _socket.setHandlers(
        read: () => _controller.add(RawSocketEvent.READ),
        write: () {
  
negative.code:         if (i == DESTROYED_EVENT) {
            assert(!isClosed);
            isClosed = true;
            closeCompleter.complete();
            disconnectFromEventHandler();
            if (handler != null) handler();
            continue;
  