Yep, or any pluggable file system. Operating systems and programming languages evolved on the assumption that it's OK for operations to take arbitrary amounts o

Yep, or any pluggable file system. Operating systems and programming languages evolved on the assumption that it's OK for operations to take arbitrary amounts of time that you can't necessarily know in advance and which may change out from underneath you, with threads being the solution (run stuff in a background thread and keep the user informed on a foreground thread). Trying to make everything async in a single thread will constantly run into papercuts like the network fs scenario because the whole infrastructure just isn't designed for it.