code: void addAveReduceSlotRefillMsecs(int refillMsecs) {
      synchronized (reduceSlotRefillMsecsQueue) {
        reduceSlotRefillMsecsQueue.add(refillMsecs);
        if (reduceSlotRefillMsecsQueue.size() >= maxRefillQueueSize) {
          reduceSlotRefillMsecsQueue.remove();
        }
      }
    }
docs: Add this new refill time for the reduce slot refill queue.  Delete
  the oldest value if the maximum size has been met.
  
  @param refillMsecs Time to refill a reduce slot