Looks like it handles two-way sync very well, but could it keep more than two participants in sync? I'm sort of "abusing" Syncthing to sync Docker volumes (mostly just configuration and helper scripts) across several hosts. It works well, and the only things I'm missing are file ownership preservation and low-latency "instant"-feeling sync. csync2 gets it right, but it's fragile and needs a lot of babysitting. I'm wondering if Mutagen might be a suitable alternative.
One way you can do this with Mutagen is to use a hub-and-spoke topology, where one copy of the files (say the one on the laptop where you're coding) is the "hub," and then you have multiple two-way (or one-way) synchronization sessions going out to the various "spoke" endpoints. In the two-way case, changes on a spoke endpoint will be propagated out to the other endpoints by first propagating to the hub. Obviously, you can have contention in this case if you have ultra-high-frequency updates to the same sets of of files, though the conflicting operations would have to occur on a smaller timescale than that of a single Mutagen synchronization cycle (which is typically somewhere around 100ms for an average codebase). Also, in the case of contention, Mutagen will simply display the conflicting files to you and you can delete the "losing" copy. You can also set auto-resolution behavior with Mutagen's `two-way-resolved` mode to let the hub win in conflicts, or use `one-way-replica` mode to make all the spoke endpoints replicas of the hub, or some combination of all these things, etc.
