If your application is timing critical, and you aren't using things specifically desiged for time critical applications (like RTOS), then you should be doing as much low level implementation yourself as possible.
Or the other way: don't make your application timing critical if it does not have to be. As others point out the hardware provides a buffer and the app only fills in one frame in advance instead of filling the buffer completely when possible.
If your application is timing critical, and you aren't using things specifically desiged for time critical applications (like RTOS), then you should be doing as much low level implementation yourself as possible.