Multicast Support

[stendec]

Datagram instances should be able to easily handle multicast.

Sending

For sending multicast packets, there should be a convenience function that sets the IP_MULTICAST_TTL option. Fortunately, Datagram.listen() already makes it easy to call bind() on the socket. However, a helper that performs both steps at once may be useful. Perhaps include IP_MULTICAST_TTL in listen()?

Receiving

Receiving multicast is much more involved than sending, given that a socket must subscribe itself to the multicast group it's interested in. This could be done in a register() method, or perhaps a connect() method to keep with standard method names.

[stendec]

I honestly can't remember why I wanted this, back when I opened it. Someone talked about it at PyCon, and I was playing with some interesting code, but the idea is dead and gone, and let's face it. Very few people use multicast. The datagram support in Pants is also pretty unimportant compared to Stream, only release used by DNS.

This issue won't be fixed.