Implement socket options

[armanbilge]

Basically, I was lazy :)

[armanbilge]

I've already implemented this in typelevel/fs2#3087, in an io-private package. When that lands we can just use it here.

[lavrov]

UDP support is coming? Looking forward to try the whole thing out!

[armanbilge]

@lavrov UDP support is definitely on my radar! It's currently blocked by lack of java.net.NetworkInterface support. Actually, Lee has already implemented that in Scala Native 0.5.x, but it proved to be too difficult to backport 😕

• WIP: 0.4.x: Backport implementation of java.net NetworkInterface & InterfaceAddress classes scala-native/scala-native#3118

I've been thinking about workarounds for this. I'd be interested if we can add a cross-platform NetworkInterface-like abstraction to ip4s, so that we have something that works on JS as well.

https://github.com/Comcast/ip4s

[LeeTibbert]

too difficult to backport Too difficult to backport hours before a release which would have no "-rc".

I am about to go on hiatus, but could try again when I return, if that would make things easier.
The Linux-like branch of the backport worked just file. The macOS branch was missing some
tricky work to deal with BSD derived sinX_len fields. I did not want to break 0.4.11 macOS people
by my attempting that on-the-fly. Time to backport is also competing against time JSR-166
concurrency work.

[armanbilge]

@LeeTibbert I appreciate all your work on that. In my humble opinion we should focus our efforts towards Scala Native 0.5, where everything is working much better anyway. I don't think it's worth the effort to backport that, instead I will try to think of some workarounds.