Documentation for `header_read_timeout` is incomplete

[jorendorff]

Three mini-issues here:

• Documentation for .header_read_timeout() doesn't mention that it requires .timer() or it'll panic.

• The example in the docs for http1::Builder uses header_read_timeout without timer. It's not meant as complete running code, but still, it's weird that if you did try to use it, you'd panic.

• No pointer to an implementation of Timer for tokio. I found a full implementation in a doc-comment, but unfortunately that's a private module.

[dswij]

The example Timer implementation for Tokio is a working example. The module is private, but we're exposing hyper::rt::{Sleep, Timer} here, which is what you'd need to implement this.

[jorendorff]

I agree with all of that. I think the three points all still stand, as opportunities for improvement. Will eventually give it a shot if nobody beats me to it.

[dswij]

That's fair. The doc for rt::{Timer,Sleep} is also asked in #3411.

[james58899]

There is an implementation available in hyper-util, maybe this can be mentioned in the documentation.

[dswij]

The docs for hyper::rt will be added in https://github.com/hyperium/hyperium.github.io/pull/121.

Will close this issue since we're also tracking it in #3411, and header_read_timeout docs were updated.

Thanks for the report @jorendorff !