protected function setMethod($method)
    {
        switch (strtoupper($method)) {
            case 'HEAD':
                curl_setopt($this->request, CURLOPT_NOBODY, true);
                break;
            case 'GET':
                curl_setopt($this->request, CURLOPT_HTTPGET, true);
                break;
            case 'POST':
                curl_setopt($this->request, CURLOPT_POST, true);
                break;
            default:
                curl_setopt($this->request, CURLOPT_CUSTOMREQUEST, $method);
        }
    }