Backport PR #20591 on branch v3.5.x (Webagg backend: get rid of tornado) - #21410

Backport PR #20591 on branch v3.5.x (Webagg backend: get rid of tornado)#21410

tacaswell merged 1 commit into

matplotlib:v3.5.xmatplotlib/matplotlib:v3.5.xfrom

meeseeksmachine:auto-backport-of-pr-20591-on-v3.5.xmeeseeksmachine/matplotlib:auto-backport-of-pr-20591-on-v3.5.xCopy head branch name to clipboard