空闲文件描述符的状态是已知的，因为在状态改变时会通知 poll 缓存服务。

The state of idle file descriptors is known since the pollcache service is notified once when it changes.

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任何改变文件最近访问时间，都会查看所在目录或子目录的变更，并将结果通知给等待操作返回。

Any change to the last access time of files in the watched directory or subtree causes a change notification wait operation to return.

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任何改变文件的创建时间的，都会查看所在目录或子目录的变更，并将结果通知给等待操作返回。

Any change to the creation time of files in the watched directory or subtree causes a change notification wait operation to return.

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