Subshells implemented using tornado event loops on 6.x branch #3337

Job	Run time
check_release	1m 40s
test_docs	38s
Test Lint	54s
Test Minimum Versions	2m 48s
build (ubuntu-latest, 3.9)	4m 59s
test_without_debugpy (ubuntu-latest, 3.9)	2m 9s
build (ubuntu-latest, 3.13)	4m 58s
link_check	3m 42s
build (windows-latest, 3.9)	7m 59s
Make SDist	29s
build (windows-latest, 3.13)	7m 45s
build (macos-latest, 3.9)	7m 42s
Test Prereleases	2m 12s
build (macos-latest, 3.13)	4m 48s
build (ubuntu-latest, pypy-3.9)	4m 23s
build (macos-latest, 3.10)	5m 4s
build (ubuntu-latest, 3.11)	4m 51s
build (ubuntu-latest, 3.12)	6m 8s
Install from SDist and Test	7m 9s
coverage	0s
	1h 20m 18s

Provide feedback