[Performance] Include TTFB metric to the timing information of a resource in the event details #63739
Description
Problem Statement
There is already a lot of valuable information in the details of a requested resource (like a script).
However, an additional field I would like to see here is TTFB because it's one of those metrics we can act upon if the request is going to one of our own CDNs, in contrast to other metrics, like download time, that are more dependent on the connection speed of the user.
Solution Brainstorm
The timing information can be obtained from this API
https://developer.mozilla.org/en-US/docs/Web/API/PerformanceResourceTiming
And even there is some code from Chrome Dev Tools that one could take inspiration from:
https://github.com/ChromeDevTools/devtools-frontend/blob/1cac27b23b595e35943fc5878b5879bf0e078965/front_end/panels/network/RequestTimingView.ts#L349-L352
(This field is referring to the value "Waiting for server response" from this image)
Product Area
Performance
┆Issue is synchronized with this Jira Improvement by Unito