On intent-based startup scenarios the browser should not issue requests like https://www.gstatic.com/chrome/intelligence/assist/ranker/models/... even with IDLE priority before the main loading starts coming along.

One way to guard against accidental requests like that is to introduce a metric that would count the number of requests started before the first navigation requests starts.

Arguably, we also should not saturate the link after loading starts, so the same logic holds true for first contentful paint. On the other hand, an extra request with IDLE priority probably causes little problems when the page is loading.