Like the patch in dev, but for 6.8 and below
We need to, following the RFC, send a Dynamic Table Size Update using
HPack once we have acknowledged the setting as long as the new size is
smaller, or if we decide to use the new, larger size.
It's further complicated by the fact that we need to send this update on
the next 'field block' (anything with headers in it), and we may have
multiple SETTING frames come in, and we need to then acknowledge the
_smallest_ one as well as the _final_ one. This is so the decoder on the
peer's side can know that we have set the smallest size, and trimmed our
tables thusly, before going to the larger size.
This could, for example, be used to clear the table.
Fixes: QTBUG-132277
Pick-to: 6.5
Change-Id: I95f006248dfcbc7952c7e184f92d8859270e9e70
Reviewed-by: Mate Barany <mate.barany@qt.io>
a428e89562