Why UDP and Unix sockets have take_error, but not Tcp sockets?

[vi]

https://docs.rs/tokio/0.3.4/tokio/net/struct.UnixListener.html?search=take_error

[taiki-e]

The direct reason tokio doesn't have that function is that mio doesn't have it.

I'm not a maintainer of mio, so I don't know the actual reason why mio doesn't have it, but I guess it's because TcpSocket was just added recently and no one ever needed that function. See also #3082.

In any case, if you need that function, I recommend opening an issue (or a pr) in mio. Once added to mio, we can add it to tokio as well.

[taiki-e]

This will be added in #4364.