Secondly, the RMD doesn't have to acknowledge the messages it has received.

其次，RMD并非必须对它已接收到的全部消息作出确认。

youdao

Note that the acknowledgement isn't just for one message, it acknowledges all the messages successfully received by the RMD.

注意，这种确认并不是与消息一一对应的，而是代表对所有由RMD成功接收的消息的确认。

youdao

This means that you can have a persistent store behind the RMD, so the acknowledgement is only sent when the message has been written to disk.

在这个实现中，只有消息被持久化到磁盘后才会发出确认消息。

youdao

One reason people are probably confused is because last year Congress issued an RMD holiday.

FORBES: Take Money Out Of Your IRA In 2010, Or Else

The law imposes a 50% excise tax on any RMD a taxpayer fails to take.

FORBES: Magazine Article

They got to take advantage of the RMD holiday, so there was no April 1 deadline in 2010.

FORBES: April 1 Deadline Looms For IRA Holders