How to get Swift Mailer Delivery/Failures/Errors Status when you sending emails

Example of send email method with using Swift_Mailer (Swift_SmtpTransport, Swift_Message)
If you want get Delivery/Failures/Errors Status you can use this construction:

 /**
     * Method for sending emails via Swift_Mailer
     * @param $email - object
     * example $email = \new StdClass();
     * $email->login = 'sender@mail.example';
     * $email->password = 'password_of_sender_email';
     * $email->host = 'imap.gmail.com'; //real example for Gmail
     * $email->first_name = 'Test Example Name';
     * $email->to = 'reciepient@mail.example'; //or array ['reciepient1@mail.example','reciepient2@mail.example','reciepient3@mail.example']
     * $email->subject = 'Example of subject';
     * $email->body = 'Example of <br/> email body message';
     * @return boolean
     */
    public static function sendEmail($email)
    {
        $isSent = $failures = false;
        try {
            $transport = \Swift_SmtpTransport::newInstance()->setHost($email->host)->setPort(465)->setUsername($email->login)->setPassword($email->password)->setEncryption('ssl');

            $mailMessage = \Swift_Message::newInstance()->setFrom([$email->login => $email->first_name])->setReturnPath($email->to)->setTo($email->to)->setSubject($email->subject)->setBody($email->body, 'text/html');

            $mailer = \Swift_Mailer::newInstance($transport);

            if ($mailer->send($mailMessage, $failures)) {
                $isSent = true;
                echo ' SUCCESS SENDING!:' . $email->login . ' to ' . $email->to;
            } else {
                echo ' SENDING ERROR TO :' . print_R($failures);
            }
        } catch (\Exception $e) {
            echo 'Catch Error with ' . $email->login . ' : ' . $e->getErrorMessage() . "\n";
        }
        return $isSent;
    }

swift_SmtpTransport / Swift_Message /Swift_Mailer