This would have helped when trying to debug <https://webkit.org/b/207346>.
Created attachment 389984 [details] Patch
Comment on attachment 389984 [details] Patch r=me, very cool. Let's wait for EWS, worker tests seem more likely to have flake issues.
Created attachment 389988 [details] Patch
Comment on attachment 389988 [details] Patch Clearing flags on attachment: 389988 Committed r255986: <https://trac.webkit.org/changeset/255986>
All reviewed patches have been landed. Closing bug.
<rdar://problem/59239652>