tree 72136e8711360a03d8f75c0b5cb8dec983e76f1a
parent 56fb53ef8de4719181f7eeaf9f0c92141f9d6ed0
author bnc <bnc@google.com> 1561162564 -0700
committer Copybara-Service <copybara-worker@google.com> 1561417890 -0700

Modify QpackInstructionEncoder API.

QpackInstructionEncoder does not need to support progressive encoding.  This CL
modifies the API, a follow-up CL will clean up internals.

Taking |&output| and appending is more performant than returning std::string
when encoding headers, which involve concatenating a large number of
instructions.

gfe-relnote: n/a, QUIC v99-only change.
PiperOrigin-RevId: 254497735
Change-Id: I62d74a0523220e5730ffc85ea66ab071345fc8fb