Helper\Mailer\Smtp::sendMail PHP Method

    public function sendMail()
    {
        $command = $this->getCommand();
        $this->_isSecurity ? $this->socketSecurity() : $this->socket();
        foreach ($command as $value) {
            $result = $this->_isSecurity ? $this->sendCommandSecurity($value[0], $value[1]) : $this->sendCommand($value[0], $value[1]);
            if ($result) {
                continue;
            } else {
                return false;
            }
        }
        //其实这里也没必要关闭，smtp命令：QUIT发出之后，服务器就关闭了连接，本地的socket资源会自动释放
        $this->_isSecurity ? $this->closeSecutity() : $this->close();
        return true;
    }