After the message is rolled back to the destination, the underlying system redelivers the message based on the destination's maximum failed delivery setting.

将消息回滚到目的地后，基础系统基于目的地的最大失败提交次数设置重新提交消息。

youdao

Subscribers can specify a maximum QoS for delivery of messages on a per-topic basis, so a message published at QoS 2 May not be delivered to its subscribers at that level.

订阅者可以基于每个主题指定消息传递的最大QoS，所以若消息在QoS 2发布，此消息有可能不是在该级别发布给其订阅者。

youdao

But to have the maximum effect (and provide the optimum experience for the user) the delivery environment needs to be created correctly.

但是，要获得最佳效果(并向用户提供最优体验)，就需要正确创建传送环境。

youdao

"DFID needs to do more and to take a tougher, clearer stance on the importance of cost and service performance information, and in particular indicators of education delivery and attainment if it is to make sure its contributions achieve the maximum good effect, " he said.

BBC: UK aid for foreign schools 'gets disappointing results'