func (pq *PriorityQueue) update(item *Item, value string, priority int) {
	item.value = value
	item.priority = priority
	heap.Fix(pq, item.index)
}
func (pq *PriorityQueue) update(item *Item, value string, priority int) {
	item.value = value
	item.priority = priority
	heap.Fix(pq, item.index)
}
func ( pq * PriorityQueue ) update ( item * Item , value string , priority int ) { item . value = value item . priority = priority heap . Fix ( pq , item . index ) }
// update modifies the priority and value of an Item in the queue.
update modifies the priority and value of an Item in the queue .