Strenghen the case against STRING_LIST in the docs.

See also: #2873

Should address "HTTP cache must not reuse a response with an invalid
Cache-Control: max-age (trailing alpha)" from https://cache-tests.fyi.

Should address "HTTP cache must not use a cached response with
Cache-Control: No-CaChE, even with max-age and Expires" from
https://cache-tests.fyi.

Fixes: #2874

Ensure ESI children are set up from preq->http0

If we timed out during polling display the correct error.  In
addition, treat all polling errors as receive errors.

Fixes #2866.

Fixes #2871.

And make the caller responsible for formally entering the task.

Someone should triple-check that it is indeed safe.

Submitted by:   Frederic Lecaille <flecaille@haproxy.com>

any more.

It turns out people are really attached to their varnish.params file.

See `git grep PROXY -- bin/varnishd/mgt/mgt_main.c`.

that should not happen.

would give subsequent esi-includes the wrong vcl.

not need it (acceptor, h2_sess)

store more stuff in it.

This reverts commit 5b6a4e56.

The moment we unlock the oh, another thread could rush req

Partially undoes f35b86bc

Huge thank you to @mbgrydeland for spotting my mistake

and polish the output formatting by reordering

Ref #1799

Ref #2743