priority = lowestPriority - j
				break
			}
		}
		priorityMap[priority] = append(priorityMap[priority], i)
	}

	// sort all priorities in increasing order.
	priorities := []int{}
	for priority := range priorityMap {
		priorities = append(priorities, priority)
	}
	sort.Ints(priorities)

	out := make([]*endpoint.LocalityLbEndpoints, len(priorityMap))
	for i, priority := range priorities {