*     down the executor after the last event has been posted to this event bus.
   */
  public AsyncEventBus(String identifier, Executor executor) {
    super(identifier, executor, Dispatcher.legacyAsync(), LoggingHandler.INSTANCE);
  }

  /**
   * Creates a new AsyncEventBus that will use {@code executor} to dispatch events.
   *
   * @param executor Executor to use to dispatch events. It is the caller's responsibility to shut