src/EventEmitterTrait.php
public function getListeners(string $event) : array
    {
        return isset($this->listeners[$event]) ? $this->listeners[$event] : [];
    }
public function getListeners(string $event) : array
    {
        return isset($this->listeners[$event]) ? $this->listeners[$event] : [];
    }
@param string $event

@return array|callable[]