HH-43096 copy as curl: use ": " instead of "=" as a delimeter for headers
Merge remote-tracking branch 'origin/HH-43096' into EXP-11202
release 2.19.10 [a.rybalkin@hh.ru]
HH-43336 new AsyncGroup.try_finish_async method
HH-42371 fix AsyncGroup implementation
HH-42371 fix docs and speed up unittests, fix PEP8