Problem wtih simultaneous parallel and dump_headers parameters in CurlClient

[voodam]

curl doesn't work with both parameters properly. This run should give various number (4, 5, 6):

curl --parallel --parallel-immediate --parallel-max 6 --dump-header /tmp/dmp.hdr https://example.com/[1-6] > /dev/null; cat /tmp/dmp.hdr | grep HTTP | wc -l

Ways to fix:

• do https://github.com/tempesta-tech/tempesta-test/issues/480, but be aware of the current issue.
• contribute to curl.
• find some workaround.

Curl version:

curl 7.85.0-DEV (x86_64-pc-linux-gnu) libcurl/7.85.0-DEV OpenSSL/1.1.1f zlib/1.2.11 nghttp2/1.40.0
Release-Date: [unreleased]