ae2471b850
By the design of task scheduler it was possible that tasks from somewhere in the middle of scheduled list will be handled first. For example, one thread might be iterating over the scheduled list and ignore tasks because there is other thread is working on task from the same pool. However, if that other thread finishes task before iteration is over current thread will pick up task from somewhere in in the middle of the list. This isn't a problem in general case, but for movie rendering we do need to have strict order of frames.