src/AbstractServer.php
public function addEventListener($eventName, callable $listener, $priority = Emitter::P_NORMAL)
    {
        $this->eventEmitter->addListener($eventName, $listener, $priority);
    }
public function addEventListener($eventName, callable $listener, $priority = Emitter::P_NORMAL)
    {
        $this->eventEmitter->addListener($eventName, $listener, $priority);
    }
public function addEventListener ( $ eventName , callable $ listener , $ priority = Emitter :: P_NORMAL ) { $ this -> eventEmitter -> addListener ( $ eventName , $ listener , $ priority ) ; }
Add an event listener to the event emitter

@param string   $eventName Event name
@param callable $listener  Callable function or method
@param int      $priority  Priority of event listener
Add an event listener to the event emitter