public function actionStop()
    {
        $message = 'Stopping Yii 2 Daemon ' . $this->version . '... ';
        $result = static::EXIT_CODE_NORMAL;
        if ($this->_getPid() !== false) {
            $this->_killPid();
            $message .= 'OK.';
        } else {
            $message .= 'Service is not running!';
            $result = static::EXIT_CODE_ERROR;
        }
        echo $message . PHP_EOL;
        $this->_log($message);
        return $result;
    }