code: public EventBus bind(Class<? extends EventObject> eventType, ActEventListener eventListener) {
          boolean async = isAsync(eventListener.getClass()) || isAsync(eventType);
          return _bind(async ? asyncActEventListeners : actEventListeners, eventType, eventListener, 0);
      }
docs: Bind an {@link ActEventListener} to an event type extended from {@link EventObject}.
  
  If either `eventType` or the class of `eventListener` has `@Async` annotation presented,
  it will bind the listener into the async repo. When event get triggered the listener
  will be invoked asynchronously.
  
  @param eventType
  the target event type - should be a sub class of {@link EventObject}
  @param eventListener
  an instance of {@link ActEventListener} or it's sub class
  @return this event bus instance