Is It Worthwhile?

Given that this is relatively complex, and could be made obsolete if --rsync or something similar were more widespread. But technologies do not exist in an ideal world; if the existing content is not adapted for rsync, then it must be allowed for. --rsync continues to be of some use even with this method, because it causes more regular block headers in the resulting gzip file. Some downloads may be more efficient using --rsync and not looking inside the compressed data, while others might be more efficient when looking inside the file. I think it is enough of an open question to warrant implementing something, and seeing whether it proves useful. The basic zsync functionality is not tied to this feature, and it could be easily dropped.