WIP RFC for Unix domain socket support

[sgebbie]

Here we provide an RFC related to introducing Unix domain socket support into the net package.

[adri326]

Rendered (latest)

[sgebbie]

Following the Pony sync 2021-11-23 the general view is that there is support for including Unix domains into the net package. However, the before moving forward with the RFC, it would be good to have some proof-of-concept code showing how this might be implemented.

That is, it might be possible to use more FFI and the existing ASIO rather than making changes to libponyrt. Or, for maintainability it might be better to follow the existing code style.