Investigate UNIX domain sockets

UNIX domain sockets may be able to accelerate intra-node inter-process communications.

In the TCP comm it may be possible to swap out the socket used if the local and peer hostnames are identical (probably made optional with configuration and dependent on OS used)

Some links from perusing the web:

- https://blog.myhro.info/2017/01/how-fast-are-unix-domain-sockets
- https://unix.stackexchange.com/questions/326510/local-unix-socket-rough-idea-of-throughput

cc @jacobtomlinson , this might interest you? (if you had a bunch of free time that is)

Previous conversation in https://github.com/dask/dask/issues/3657#issuecomment-603275248