bool hasListeners(string $eventName = null) Checks whether an event has any registered listeners

class RegisterListenersPass implements

removeSubscriber(

mixed getArgument(string $key) Get argument by key.

int|null getListenerPriority(string $eventName, callable $listener) Gets the listener priority

interface TraceableEventDispatcherInterface implements

int|null getListenerPriority(string $eventName, callable $listener) Gets the listener priority

bool hasArgument(string $key) Has argument.

array getCalledListeners() Gets the called listeners.

class GenericEvent extends Event