http2: add altsvc support
Add support for sending and receiving ALTSVC frames.
As defined by https://tools.ietf.org/html/rfc7838
ping @nodejs/http2
Checklist
-
make -j4 test
(UNIX), orvcbuild test
(Windows) passes -
tests and/or benchmarks are included -
documentation is changed or added -
commit message follows commit guidelines
Affected core subsystem(s)
http2