std::net::UdpSocket::recv_from() returns Result<(usize, SocketAddr)>. mio::udp::UdpSocket.recv_from() returns Result<Option<SocketAddr>>.
02:18 <~ carllerche> if you could file an issue w/ API inconsistencies that you are aware of... would be good
Unaware of more, but this could be an issue for taking notes of such things.