In the VSE, when using Prefetch Frames, keep a little bit of cached frames behind the playhead.

Now with prefetch option ON, all the cached frames are only in front of the playhead. This is good for regular playback, but that prevent you from doing a slight scrub back and forth smoothly because the played frames are immediately deleted from the cache once they are played.

I would like the possibility to keep a certain portion of the total cached frames to be on the already played frames.

for example, instead of a ticking box to activate "prefetch frames", we can have a slider to set a % of the memory to dedicate to prefetch, and keep the rest of the memory for caching the frames already played.