The fundamental reason the action handler extension point exists is to allow for existing event - or message-based systems to contribute actions to the declarative broker model.
存在操作处理程序扩展点的根本目的在于：允许现有基于事件或消息的系统将操作用于声明式代理模型。
2
He had no reason to have brought a fork along to this event, a wedding that he could have been reasonably sure would be providing its own silverware.
他没理由从家里带把叉子到婚礼上，婚礼上有银器，他早就知道的。
3
Many STL containers let you play the same trick. Most programmers wouldn't call the qsort callback an event, but there's no reason you can't think of it that way.