public static function ipWithProxy($delimiter = ','): string
    {
        $ip = self::ip();

        if (isset($_SERVER['HTTP_X_FORWARDED_FOR']) && $ip != $_SERVER['HTTP_X_FORWARDED_FOR']) {
            $ip .= "{$delimiter}{$_SERVER['HTTP_X_FORWARDED_FOR']}";
        }

        return $ip;
    }