Feedback on prefetching on leaf nodes in BKD tree traversal.

Hello team,

I am looking for a way to add prefetching in leaf nodes (kdd) in bkd tree
traversal. At a high level, during the tree traversal for conditions when
cell is inside the query I am caching the file pointer for doc ids in kdd
index also calling prefetch for them. Rest of the recursion remains as is.

Once I am done with the recursion, I am visiting the doc ids from cached
file pointers.

This is the POC PR that I have
https://github.com/apache/lucene/pull/15376/files

Any feedback/ input is greatly appreciated.

Thanks
Saurabh