protected function _setSmtpProtocol($url)
    {
        $protocol = '';
        $smtpHost = $url;
        $match = [];
        if (Str::getStr()->preg_match('@^([0-9a-z]+://)?(.*)$@i', $url, $match)) {
            if ($match[1]) {
                if (($match[1] == 'ssl://') || ($match[1] == 'tls://')) {
                    $this->set("SMTPSecure", substr($match[1], 0, 3));
                } else {
                    $protocol = $match[1];
                }
            }
            $smtpHost = $match[2];
        }

        return $protocol . $smtpHost;
    }