Move UDS types to unix module

[Thomasdezeeuw]

Currently the UDS types (UnixDatagram, UnixListener, UnixStream) currently live in the net module, but they are Unix only. Shouldn't these live in the unix module (following what std lib does)? Or perhaps in mio::unix::net.

If Windows (or more platforms) ever get support for them we can always moves them, leaving alias in the unix module.

/cc @kleimkuhler

[DoumanAsh]

If Windows (or more platforms) ever get support for them we can always moves them, leaving alias in the unix module.

JFYI some newer versions of Win10 supports it

[Thomasdezeeuw]

JFYI some newer versions of Win10 supports it

Good to know, but Mio doesn't (yet) support them.

[kleimkuhler]

I think this would be a good idea. Using UnixListener for example requires std::os::unix::net::UnixListener, so I think mio::unix::net makes the most sense.

[carllerche]

I believe that keeping platform specific types in separate modules & trait extensions has been considered a "mistake". Instead, types should just be where they make natural sense and use feature flags to enable / disable.

So i would recommend to follow this guidance.

[Thomasdezeeuw]

@carllerche the blog post makes a lot of good points, I'm ok with leaving it the net module. Do you want to the same for SourceFd (and possible future Windows counterpart)? I'm not sure where they would move to though.

Also should more documentation be added that they're Unix only, I know the name suggests it but still. The API in the standard library have a clear blue box, e.g. see https://doc.rust-lang.org/std/os/unix/net/struct.UnixStream.html, but I don't know if that is available for user code yet.

[arsing]

(UDS support on Windows previously discussed in #880 )

[Thomasdezeeuw]

Not doing this, leaving the UDS types in the net module.