public function add_event_listener(string $event)
    {
        // Automatically instantiate this class
        if ( class_exists("\App\Boot") ) {
            // Excute a boot instance
            $boot = new \App\Boot();

            if ( method_exists($boot, $event) ) {
                call_user_func([$boot, $event], $this->server);
            }

            // Listen Background task listener
            if ($event == 'onBoot') {
                $this->server->on('task', [$boot, 'onTask']);
                $this->server->on('finish', [$boot, 'onFinish']);
            }
        }
    }