Improve handling for cases where maximum in-flight command buffer count is exceeded. This can occur during light-baking operations. Ensures the application handles this gracefully and also improves workload pipelining by situationally stalling until GPU work has completed, if too much work is queued up.
This may have a tangible benefit for T103742 by ensuring Blender does not queue up too much GPU work.
Authored by Apple: Michael Parkin-White