public function sendMail(Mail $mail) {
		$sender = $mail->getSender();
		if (!$sender instanceof MailAddress) {
			throw new SmtpException('no sender found on mail');
		}
		$this->mail($sender->getEmail());
		
		foreach ($mail->getRecipients() as $address) {
			$address instanceof MailAddress;
			// @todo: catch errors
			$this->recipient($address->getEmail());
		}
		
		$this->data($mail->getData());
	}