readsInFlight property

Reads started here and not finished — the count a scenario reads to know that work it cannot see is genuinely in flight, rather than taking a turn of the real event loop to guess. See landRealWork.

Everything an app reads through the bundle passes here, so an SvgPicture.asset or a Lottie.asset is counted for as long as its bytes are on the way — the part of those loads that costs the most and announces the least. The decode on the other end is not in it. A quick one lands on a guessed turn; a parse in an isolate — Lottie's backgroundLoading — can outlast every turn, and is the app's to announce through RealWork.