Feature #3168
Updated by Junxiao Shi about 9 years ago
Implement `UdpTransport` for use with LinkService. The `UdpTransport` is a subclass of [`Transport`](https://gist.github.com/yoursunny/22a7d53711b4e9bc198a) that communicates with either one a remote forwarder or a multicast group over a UDP socket. * `UdpTransport` is always non-local. * `UdpTransport` can be on-demand, persistent, or permanent. After implementing `UdpTransport`: * change `UdpChannel` to initialize an `LpFace(SimpleLinkService+UdpTransport)` in place of `UdpFace` * delete old `UdpFace` and `MulticastUdpFace`