AF_UNIX, SOCK_DGRAM sockets are valid, but asyncio doesn't appear to support them.

I've tried combinations of create_connection, create_datagram_endpoint and create_unix_connection, creating a socket myself and passing in sock, and equivalent methods at the server end. There seem to be implicit assumptions about addresses being 2-tuples (instead of strings) and transports being hardcoded to be constructed as either stream or datagram transports. create_unix_connection makes the assumption that it will be a stream, and create_datagram_endpoint that it will be AF_INET or AF_INET6 with (host, port) addressing.

I used 3.4.3, but looking at the docs it doesn't look like this was addressed in 3.5 either.

I'd like this because message boundaries are preserved (unlike in SOCK_STREAM), which if it Just Worked would make local system IPC (eg. with JSON-RPC) extremely trivial to implement in asyncio.