Kue.js Worker process...

I am trying to replace AWS SQS with Kue.js in a node application.
My concern is, if there are n no of items added in a queue. How many items in the queue will be processed concurrently??
Is it like.... processor will process the each item one at a time or in bulk??
Also if the queue.process() is called for the same queue from two or more different places. how will the processing be done. Kindly suggest

Start at the queue.process() entry point and review the existing worker and queue documentation. Document how many jobs a queue processes concurrently and how multiple process() calls for the same queue behave; the issue is complete when both cases are explained clearly.

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