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

removeSubscriber(

array getListeners(string $eventName = null) Gets the listeners of a specific event or all listeners

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

bool hasArgument(string $key) Has argument.

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

addSubscriber(

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

removeSubscriber(

array getListeners(string $eventName = null) Gets the listeners of a specific event or all listeners