protected function pack($data, $statusCode=200, $message=null)
    {
        $packBody = [];

        // Status Code
        if ($statusCode) {
            
            $packBody['code'] = $statusCode;
        }
        // Message
        if ($message) {
            
            $packBody['message'] = $message;
        }
        // Data
        if (is_array($data) || is_string($data)) {
            
            $packBody['data'] = $data;
        }
        
        return $packBody;
    }