code: @Override
  	public void postDelayed(Object event, long delayMillis) {
  		if (event == null) {
  			throw new NullPointerException("Event must not be null");
  		}
          Handler handler = getMainHandlerNotNull();
          if (handler.getLooper().getThread().isAlive()) {
  		    mImpl.postDelayed(event, delayMillis, handler);
          } // otherwise the bus is already stopped
  	}
docs: -- delayed tasks (experimental)