code: func txPQByPriority(pq *txPriorityQueue, i, j int) bool {
  	// Using > here so that pop gives the highest priority item as opposed
  	// to the lowest.  Sort by priority first, then fee.
  	if pq.items[i].priority == pq.items[j].priority {
  		return pq.items[i].feePerKB > pq.items[j].feePerKB
  	}
  	return pq.items[i].priority > pq.items[j].priority
  
  }
docs: // txPQByPriority sorts a txPriorityQueue by transaction priority and then fees
  // per kilobyte.