tree 27cd2ac117cfaede662a2adacd8e72df20e08b87
parent c06ea15fb70cf290667de767d9862ba8ef3a76e9
author bnc <bnc@google.com> 1656093569 -0700
committer Copybara-Service <copybara-worker@google.com> 1656093636 -0700

Add HttpEncoder::SerializeMetadataFrameHeader().

Add HTTP/3 SETTING_ENABLE_METADATA.
Add HTTP/3 METADATA frame type.
Add HttpEncoder::SerializeMetadataFrameHeader() method to serialize METADATA frame header.

Setting identifier and frame type match HTTP/2 ones, see
quiche/spdy/core/metadata_extension.cc.

See https://github.com/envoyproxy/envoy/issues/2394 and design document linked
therein for HTTP/2 METADATA.  HTTP/3 implementation will be very similar.

PiperOrigin-RevId: 457048873