This makes it highly efficient but means that client notification of events is delayed until the client makes an unrelated call.
这使它具有较高的效率，但也意味着客户机事件通知被延迟到直到发生另一个不相关的客户机调用。
2
If you wanted the queued item to do something else, you would need to add that to the implementation of the Delayed object and call that new method upon retrieval from the queue.