Function parallel_batch_process 

pub fn parallel_batch_process<T, U, F, P>(
    items: &[T],
    batch_size: usize,
    processor: F,
    progress_callback: P,
) -> Vec<U>
where
    T: Sync,
    U: Send,
    F: Fn(&[T]) -> Vec<U> + Sync,
    P: Fn(usize, usize) + Sync,

Parallel batch processing with progress tracking

Processes items in batches and provides progress information. Useful for long-running operations where progress feedback is needed.