Invalid layout assumptions for std::net::SocketAddrV{4, 6}

[a1phyr]

https://github.com/spacejam/rio/blob/319f7fb04014aa88540c3539bd97d5a0006a1eb9/src/io_uring/uring.rs#L733-L752

This code assumes that the layout of std::net::SocketAddrV{4,6} matches libc::sockaddr, but std makes no such promise. See rust-lang/rust#78802 for more details.

Example fixes: tokio-rs/mio#1388, rust-lang/socket2#120.