Other than that I don't really have anything meaningful to say about it. It could probably use a bit more traces for debugging.
I believe there's some discussion on https://gitlab.winehq.org/wine/wine/-/merge_requests/7236#note_95147 about whether this protocol is the right one to use. This one looks simpler, though I don't really have an opinion. It's working fine with labwc as far as I can tell.