feat(server): add AutoConnection

[programatik29]

Closes hyperium/hyper#2852.

This utility automatically detects HTTP protocol and uses its implementation.

[seanmonstar]

Excellent start, thanks! I appreciate how the tests are really easy to follow, that it indeed works for both versions.

Do we need to bump the CI config to make those jobs happy? Could do so in a separate PR that is easier to review/merge.

[programatik29]

Do we need to bump the CI config to make those jobs happy?

I have no idea what is wrong with CI. It seems like the source is dependencies.

[seanmonstar]

I'm increasing the MSRV in #13, I think the Miri failures need those tests to be disabled for Miri (#[cfg(not(miri))]).

[bossmc]

Hi, @seanmonstar pointed me at this MR since I'd implemented something similar as part of hyperium/hyper#3084, I've added some comments from comparing how I did it in hyper directly compared to how you've done things here.

[seanmonstar]

What's the status here? I see you added some new commits, is this ready for a re-review?

[programatik29]

What's the status here? I see you added some new commits, is this ready for a re-review?

Yes.

[seanmonstar]

This is excellent, I love it! I had one cosmetic idea that I wrote up inline.

[seanmonstar]

Oh, now I see how you've done this. That's clever! I like the way it looks down in the unit tests.

I was slightly confused why both sub-builders had serve_connection methods, and now seeing this one here, I understand. I have a suggestion, and while I kinda like it, I'm open to hearing why it might be worse:

What if each method on the sub-builder returned, not &mut Self, but &mut Builder<E>? The builders in Finagle work the same way: a sub-builder is only usable once, and then you get back the full thing. It does make it easier to access options that affect both versions, if we were to add any.

So:

Builder::new(exec)
    .http1().keep_alive(true)
    .http1().writev(true)
    .http2().enable_connect_protocol(true)
    .max_send_buf(16324) // hypothetical, applies to both versions
    .serve_connection(io, svc);

[programatik29]

I'm open to it. I think we should ask users somehow on which one they prefer. Personally, I can work with both.

[seanmonstar]

There was an informal poll, and the current API was preferred, so let's merge with that. Thanks for all the work putting this together!

[seanmonstar]

@programatik29 would you have availability to resolve the merge conflicts? Or should I try to do so in a new PR?

[programatik29]

@seanmonstar client module is generating errors which isn't related to this PR.

[seanmonstar]

@programatik29 fixed.