Implement parallel Map & Reduce

Hi Team ,

We are using workerpool for executing certain functions for an array of items.

As of current implementation, the full array is passed onto all the workers for processing.
Ideally we would want a map & reduce functionality where the array is distributed among the workers in chunks and the workers upon completion return the worked upon array.

Any direction on helping achieve that would be great. We can open for any contributions to the code if reqd.