Windows support?

[goodboy]

Great project friends!

I just added support for trio-run-in-process in a little SC (structured concurrent) actor framework I've been working on. trip (trio-run-in-process) is giving me more reliable nested actor pool spawning then multiprocessing (though lesser performance) which is quite nice.

I was wondering, the trio subprocess stuff is supposedly supported on windows but I've hit some snags due to the usage of trio.hazmat.FdStream which isn't supported for windows (according to discussion in python-trio/trio#824, comments in #5, and python-trio/trio#174).

You can see the error in my CI build here:
https://travis-ci.org/goodboy/tractor/jobs/640131056?utm_medium=notification&utm_source=github_status

I'm not a windows pusher by any means but I do have users that would likely find it useful.
I figured I would just create an issue such that I have something to link to from tractor and to provide a start point for someone interested in trying to get this working.