Why no alternate compression algorithms in rsync?

I was thinking the other day, gzip is all fine and good, but why doesn’t rsync support other compression methods? There are a few use cases where using LZO (a very low latency compression algorithm) would be a better choice.

One such case would be when operating with a relatively slow CPU, such as on an old system or an embedded device. LZO should still get the job done quickly.

Another case is where you’re transferring files over a fast network, but moving so much data that you still want some compression in effect. In this case, gzip -1, while fast, may still be slowing down the transfer too much to take full advantage of the available bandwidth. On anything but the slowest CPUs, LZO should give near-line speed performance.