https://developer.mozilla.org/en-US/docs/Web/API/PerformanceResourceTiming/workerStart
PerformanceResourceTiming: workerStart property - Web APIs | MDN
The workerStart read-only property of the PerformanceResourceTiming interface returns a DOMHighResTimeStamp immediately before dispatching the FetchEvent if a...
web apispropertymdn
https://bugzilla.mozilla.org/show_bug.cgi?id=1606694
1606694 - [wpt-sync] Sync PR 21004 - Test for workerStart-tao-protected.https.html
RESOLVED (wptsync) in Core - Performance: General. Last updated 2020-01-02.