src/Leevel/Mail/Mail.php
protected function sendMessage(Swift_Message $message): int
    {
        return $this->connect->send($message, $this->failedRecipients);
    }
protected function sendMessage(Swift_Message $message): int
    {
        return $this->connect->send($message, $this->failedRecipients);
    }
发送消息对象

@param \Swift_Message $message

@return int