public static function toQueryString($options = array())
    {
        $temp = array();
        uksort($options, 'strnatcasecmp');
        foreach ($options as $key => $value) {
            if (is_string($key) && !is_array($value)) {
                $temp[] = rawurlencode($key) . '=' . rawurlencode($value);
            }
        }
        return implode('&', $temp);
    }