Draft: Allow UDP sockets to be connected to a remote address, and allow the...
Modifications:
- Fix bug that leads to panic when an interface does not have IPv6 source addresses
- Add IPv6 flag to IpListenEndpoint, so we can still distinguish IPv4 and IPv6 when addr == None
- Allow UDP sockets to be connected to a remote address, and allow the "established-over-unconnected" technique