public function setDefaultUserAgent()
{
$user_agent = 'PHP-Curl-Class/' . self::VERSION . ' (+https://github.com/php-curl-class/php-curl-class)';
$user_agent .= ' PHP/' . PHP_VERSION;
$curl_version = curl_version();
$user_agent .= ' curl/' . $curl_version['version'];
$this->setUserAgent($user_agent);
}