util.concurrent tests under Guava.

    The problem is that GWT responds poorly to two .gwt.xml files in the same
    Java package; see
    https://groups.google.com/g/google-web-toolkit-contributors/c/CqYH59Dt_rQ/m/uVGW1QdUsXUJ
    for details.

    The summary is that it ignores one file in favor of the other.
    util.concurrent, like nearly all our packages, has two .gwt.xml files: one

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	return nil
}

// IAMStorageAPI defines an interface for the IAM persistence layer
type IAMStorageAPI interface {
	// The role of the read-write lock is to prevent go routines from
	// concurrently reading and writing the IAM storage. The (r)lock()
	// functions return the iamCache. The cache can be safely written to
	// only when returned by `lock()`.
	lock() *iamCache
	unlock()
	rlock() *iamCache

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     * well as create and last write times. This method is almost twice as
     * efficient as manually copying as it employs an additional write
     * thread to read and write data concurrently.
     *
     * It is not possible (nor meaningful) to copy entire workgroups or
     * servers.
     *
     * @param dest the destination file or directory

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