public function sigForceShutdown($sig)
    {
        switch ($sig) {
            case SIGTERM:
                $sig = 'TERM';
                break;
            case SIGINT:
                $sig = 'INT';
                break;
            default:
                $sig = 'Unknown';
                break;
        }

        $this->log($sig.' received; force shutdown worker', Logger::DEBUG);
        $this->forceShutdown();
    }