This header is of particular benefit in a multi-client environment, as it can be used to delete or update an entry only if it hasn't already been changed since it was last read.
该头部在多客户端环境中尤其有用，因为它可用于删除或更新自上次读取以来未发生更改的条目。
Update: Some of the Facebook integration in Skype for Windows appeared in October of last year, although Skype today is reporting it as new functionality.
更新附注：尽管去年10月已经开始出现整合了facebook功能的skype应用，不过现在skype仍将这些当做最新功能来发布。
Update: Some of the Facebook integration in Skype for Windows appeared in October of last year, although Skype today is reporting it as new functionality.
更新附注：尽管去年10月已经开始出现整合了facebook功能的skype应用，不过现在skype仍将这些当做最新功能来发布。
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