How to obtain peer_addr in UdpSocket?

[PragmaTwice]

I know that tokio::net::UdpSocket can be stateless, but a peer_addr should be stored in UdpSocket after UdpSocket::connect is called (even std::net::UdpSocket has a UdpSocket::peer_addr).
I do not want to store (UdpSocket, SocketAddr) into my map because the SocketAddr should be stored inside UdpSocket.

[taiki-e]

This will be added in #4362.

[JamesHallowell]

Hey @taiki-e, it looks like #4362 was merged and then reverted. Is it going to be added back in at some point? Thanks.

[Noah-Kennedy]

I believe this was reverted due to a revert to an earlier version of mio, so this should come back soon.

[taiki-e]

re-added in #4611