Upgrade header which advertises protocol support being treated as an actual upgrading

[unarist]

from RFC7230 sec. 6.7:

A server MAY send an Upgrade header field in any other response to advertise that it implements support for upgrading to the listed protocols, in order of descending preference, when appropriate for a future request.

However, current http.rb treats it as an actual upgrading, and doesn't process response body.

c.f. nodejs/http-parser#363

[Gargron]

👍

[tarcieri]

Picking up the discussion from #508, hey @ixti, is #433 still the path forward on that?

Perhaps we should open an upstream issue about this on http_parser.rb (unless there already is one?)

[janko]

@tarcieri Considering that http_parser.rb doesn't work on JRuby 9.2.0.0, I think the path forward really is switching to http-parser gem, but I also want to hear what @ixti thinks. http-protocol also looks like a good option, if we want pure Ruby.

[tarcieri]

Last time I benchmarked a pure Ruby parser versus the Node parser, it was multiple orders of magnitude difference in performance...

[ixti]

Yeah. my plan was to switch to http-parser but with shim for it (I don't like it's API).

[tarcieri]

@ixti that's basically what you were working on in #433, right?

[ixti]

@tarcieri Yup!