* For async dispatch, an {@linkplain #immediate() immediate} dispatcher should generally be
   * preferable.
   */
  static Dispatcher legacyAsync() {
    return new LegacyAsyncDispatcher();
  }

  /**
   * Returns a dispatcher that dispatches events to subscribers immediately as they're posted

   *     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.
   *