Swift_Mailer，空的SMTP响应，使用ArrayLogger

I am sending email via amazon web services.

Using Swift_Mailer - I need to receive message id that is printed by the smtp server. If I use PHPMailer - then I enter an action_function which receives this in $extra['smtp_transaction_id'], but if I use Swift_Mailer - then I get an empty response, why? How to sovle this?

Code exmaple:

    $this->logger = new \Swift_Plugins_Loggers_ArrayLogger();
    $this->mailer->registerPlugin(new \Swift_Plugins_LoggerPlugin($this->logger));
    $isSent = $this->mailer->send($message);
    var_dump($this->logger->dump());exit;