Problem Statement

We already take advantage of the https://developer.mozilla.org/en-US/docs/Web/API/Resource_Timing_API/Using_the_Resource_Timing_API to capture network timing about resources getting loaded in.

We grab info about transfer size here:

Solution Brainstorm

Like getsentry/sentry#36012, let's comb through all the resource spans and aggregate their timing data into measurements.

This will allow us to draw insights about total assets loaded and how many resource bytes we are loading on a page.

There is an argument here that we can do this automatically in Relay to save bundle size, as we are just looking at the resource.X spans anyway.