[realloc]

I built something similar for a personal project (though not using the FUSE API) with Samba running locally. Samba has a VFS API which isn’t terrible complicated and lets you accomplish mostly the same thing: https://wiki.samba.org/index.php/Writing_a_Samba_VFS_Module

The only problem I ran into was not being able to bind to 127.0.0.1:445, or connect to a different port, on Windows. I ended up writing a small pcap program that would look for packets going out to some other ip and replay them back at localhost on the port samba was running on, so Windows thought it was connecting to a remote machine. It was a ridiculous solution and I’m sure there’s a better way, but it worked for what I needed.