ThrusterIO / event-emitter

     *

     * @return $this

     */

    public function once(string $eventName, callable $listener) : self

    {

        $onceListener = function (EventInterface $event) use (&$onceListener, $eventName, $listener) {

            $this->removeListener($eventName, $onceListener);

            call_user_func($listener, $event);

        };

        $this->on($eventName, $onceListener);

        return $this;

    }

    /**

     * @param string   $eventName

     *

     * @return $this

     */

    public function once(string $event, callable $listener) : self

    {

        $onceListener = function () use (&$onceListener, $event, $listener) {

            $this->removeListener($event, $onceListener);

            call_user_func_array($listener, func_get_args());

        };

        $this->on($event, $onceListener);

        return $this;

    }

    /**

     * @param string   $event