BuildBarn's nfsv4 server looks great!

I'm not too sure about NFSv4 for ZeroFS specifically, the benefits don't seem _that_ obvious to me, especially compared to something like 9P, where server-side locking in the ".L" version is native anyway. Especially considering that most ZeroFS users are mounting the fs on the same box as the server is running and so local locks are working.

MacOS is a bit of a blind spot for 9P though, and a client there would be great.