unansweredFrames property
Frames this settle asked for that the engine never drew.
Counted apart from frames because an app can be running and drawing
nothing at all, and that has to be visible in the reply. Found on an iOS
simulator booted with the Simulator app closed: the app sits inactive,
Flutter keeps frames enabled (it turns them off only for hidden and
paused), and no vsync ever answers them. Every tap there is delivered
and nothing it changes is built.
Implementation
final int unansweredFrames;