派发事件 {#2自定义事件}

EventDispatcher::dispatch($eventName, Event $event = null)

绑定监听事件

EventDispatcher::addListener($eventName, $listener, $priority = 0)

EventDispatcher::removeListener($eventName, $listener)

* @param eventName

EventDispatcher::hasListeners($eventName = null)

EventDispatcher::getListeners($eventName = null)

例子：

绑定多事件监听类

EventDispatcher::addSubscriber(EventSubscriberInterface $subscriber)

EventDispatcher::removeSubscriber(EventSubscriberInterface $subscriber)