private function getDefaultCurlOptions()
    {
        return array(
            CURLOPT_POST => true,
            CURLOPT_USERAGENT => $this->config['UserAgent'],
            CURLOPT_VERBOSE => false,
            CURLOPT_HEADERFUNCTION => array($this, 'headerCallback'),
            CURLOPT_RETURNTRANSFER => true,
            CURLOPT_SSL_VERIFYPEER => true,
            CURLOPT_SSL_VERIFYHOST => 2
        );
    }