Build id is an optional unique identifier specified during cdc_rsync build via CDC_BUILD_VERSION definition.
If build id specified on both client and server components it will be used to check the version of server component instead of file size + modified time.
CDC RSync is a command line tool / library for uploading files to a remote machine in an rsync-like
fashion. It quickly skips files with matching timestamp and size, and only transfers deltas for
existing files.