code: func makeSortedSequences(sequences map[uint64]int64) []uint64 {
  	results := make([]uint64, 0, len(sequences))
  	for seq := range sequences {
  		results = append(results, seq)
  	}
  	sort.Sort(bySeq(results))
  	return results
  }
docs: // Returns an array of message sequence numbers ordered by sequence.