anchor.diff:  }
   
   ReceivePort _lazyPort;
  -patch ReceivePort get port() {
  +patch ReceivePort get port {
     if (_lazyPort === null) {
       _lazyPort = new ReceivePort();
     }
  
positive.code:     _fillStatics(_globalState.currentContext);
      _lazyPort = new ReceivePort();
      replyTo.send(_SPAWNED_SIGNAL, port.toSendPort());
      
      if (_window != null)  {
        _globalState.currentContext.eval(
            () => _setTimerFactoryClosure(_timerFactory));
  
negative.code:  * are actually available.
   */
  class _WorkerStub implements _ManagerStub native "*Worker" {
    get id => JS("Object", "#.id", this);
    void set id(i) { JS("void", "#.id = #", this, i); }
    void set onmessage(f) { JS("void", "#.onmessage = #", this, f); }
    void postMessage(msg) => JS("Object", "#.postMessage(#)", this, msg);
  