function check($email, $expectedSmtp = null)
{
    $d = new PostmanSmtpDiscovery($email);
    $smtp = $d->getSmtpServer();
    $displaySmtp = $smtp;
    if ($smtp == $expectedSmtp) {
        print '.';
        return true;
    } else {
        print sprintf("\n%s: %s smtp=%s\n", 'Fail', $email, $displaySmtp);
        return false;
    }
}
 /**
  * This Ajax function retrieves the smtp hostname for a give e-mail address
  */
 function getAjaxHostnameByEmail()
 {
     $goDaddyHostDetected = $this->getBooleanRequestParameter('go_daddy');
     $email = $this->getRequestParameter('email');
     $d = new PostmanSmtpDiscovery($email);
     $smtp = $d->getSmtpServer();
     $this->logger->debug('given email ' . $email . ', smtp server is ' . $smtp);
     $this->logger->trace($d);
     if ($goDaddyHostDetected && !$d->isGoogle) {
         // override with the GoDaddy SMTP server
         $smtp = 'relay-hosting.secureserver.net';
         $this->logger->debug('detected GoDaddy SMTP server, smtp server is ' . $smtp);
     }
     $response = array('hostname' => $smtp, self::IS_GOOGLE_PARAMETER => $d->isGoogle, 'is_go_daddy' => $d->isGoDaddy, 'is_well_known' => $d->isWellKnownDomain);
     $this->logger->trace($response);
     wp_send_json_success($response);
 }