Function worker_pk_range 

fn worker_pk_range(
    splits: &PkBoundaries,
    worker_id: usize,
    owner_worker_id: usize,
    worker_count: usize,
) -> Option<PkRange>

This worker’s PK range, or None if it owns no partition. Rotating the partition by the table’s owner keeps the open-ended ranges from always landing on the same workers.