MEDIUM: mux-h2: implement emission of H2 headers frames from HTX blocks

When using HTX, we need a separate function to emit a headers frame.
The code is significantly different from the H1 to H2 conversion, though
it borrows some parts there. It looks like the part building the H2 frame
from the headers list could be factored out, however some of the logic
around dealing with end of stream or block sizes remains different.

With this patch it becomes possible to retrieve bodyless HTTP responses
using H2 over HTX.
1 file changed