public function beforeSendPerformed(Swift_Events_SendEvent $event)
    {
        $message = $event->getMessage();

        $to = $this->filterEmailArray((array) $message->getTo());
        $cc = $this->filterEmailArray((array) $message->getCc());
        $bcc = $this->filterEmailArray((array) $message->getBcc());

        $message->setTo($to);
        $message->setCc($cc);
        $message->setBcc($bcc);

        $all = $to + $cc + $bcc;

        if (empty($all)) {
            $event->cancelBubble();
        }
    }