RunnableExecutorPair list;
      synchronized (this) {
        if (executed) {
          return;
        }
        executed = true;
        list = runnables;
        runnables = null; // allow GC to free listeners even if this stays around for a while.
      }
      while (list != null) {
        executeListener(list.runnable, list.executor);
        list = list.next;
      }
    }

      RunnableExecutorPair list;
      synchronized (this) {
        if (executed) {
          return;
        }
        executed = true;
        list = runnables;
        runnables = null; // allow GC to free listeners even if this stays around for a while.
      }
      while (list != null) {
        executeListener(list.runnable, list.executor);
        list = list.next;
      }
    }