code: func (s *UtxoScanner) dequeueAtHeight(height uint32) []*GetUtxoRequest {
  	s.cv.L.Lock()
  	defer s.cv.L.Unlock()
  
  	// Take any requests that are too old to go in this batch and keep them for
  	// the next batch.
  	for !s.pq.IsEmpty() && s.pq.Peek().BirthHeight < height {
  		item := heap.Pop(&s.pq).(*GetUtxoRequest)
  		s.nextBatch = append(s.nextBatch, item)
  	}
  
  	var requests []*GetUtxoRequest
  	for !s.pq.IsEmpty() && s.pq.Peek().BirthHeight == height {
  		item := heap.Pop(&s.pq).(*GetUtxoRequest)
  		requests = append(requests, item)
  	}
  
  	return requests
  }
docs: // dequeueAtHeight returns all GetUtxoRequests that have starting height of the
  // given height.