core.async would be nice

[JulianBirch]

It's perfectly possible to implement on top, of course...

[charles-dyfis-net]

My impression is that one couldn't really put the blocking parts in a goroutine without being a bad citizen, unless there's a non-blocking alternative to WatchService that I've missed.

Thus, any well-behaved implementation would end up doing the polling work in a separately-managed thread regardless.