Use the polling crate in xclock_utc example

[notgull]

Using an established ecosystem crate for polling is probably better than using system calls.

[psychon]

Thanks. This seems convincing. "Going epoll" might be a bit too much for this, but getting rid of #[cfg] is definitely nice.

While looking at the polling crate, I came across their use of the log (and an issue to switch to tracing). What do you think: Would it make sense to add one of these as an (optional) dependency to x11rb?

[psychon]

For future me: There was a successful AppVeyor build of the current state of things.

[notgull]

While looking at the polling crate, I came across their use of the log (and an issue to switch to tracing). What do you think: Would it make sense to add one of these as an (optional) dependency to x11rb?

The only reason we aren't using tracing is because tracing has an MSRV of 1.56 and the MSRV for polling is currently limited to the current Debian Stable (1.48, hopefully being bumped soon, see smol-rs/smol#244). I would support adding tracing logging to this crate.

[psychon]

Okay, thanks. I'm not quite sure about log vs tracing, but they seem interoperable in both directions...

I would support adding tracing logging to this crate.

Also if I were to make it an optional dependency and hack together an abstraction to make that possible? 🙈