Maybe make a custom Http2HeaderEncoder

[carl-mastrangelo]

Currently the default Netty Http2HeaderEncoder grabs an iterator from an Http2Headers objects and iterates over the values, adding them to the table and serializing them to a ByteBuf. We could save on a lot of allocations and cputime if we could pass an array directly in and skip Iterator. We don't even have to deal with the hpack portions of this since we can reuse that API independent of the Http2HeaderEncoder interface.

[nmittler]

Should we create a Netty issue for this?

[carl-mastrangelo]

It's really hard for me to tell. Considering that this hasn't been a pain point for other Netty users (or, enough for them to file issues for), I don't think so. The improvements I am thinking about are going to be increasingly specific to gRPC, and take advantage of our special use.

That said, this is not a high importance issue at the moment. The hpack encoder is way more expensive than this proposed change at the moment.