This is part of a bigger change that will facilitate us
to act on this `RasterStatus`. The specific case is where
after pre-roll we might decide to want to merge the threads
and re-submit the frame -- `RasterStatus::kResubmit` can then
let us achieve this result.
Flow is a simple compositor based on Skia that the Flutter engine uses to cache
recoded paint commands and pixels generated from those recordings. Flow runs on
the GPU thread and uploads information to the GPU.