code: public boolean dispatchAsyncOnce(DispatchTask task, long delayMillis) {
  		if (!task.isScheduled()) {
  			dispatchAsync(task, delayMillis);
  			return true;
  		}
  		return false;
  	}
docs: Add <code>{@link DispatchTask}</code> to the queue if it's not already on the queue (this
  way you can ensure only one instance of the task is scheduled at a time). After the task is
  executed you can schedule it again.
  
  @return true if task was scheduled