code: func NewTruncIndex(ids []string) (idx *TruncIndex) {
  	idx = &TruncIndex{
  		ids: make(map[string]struct{}),
  
  		// Change patricia max prefix per node length,
  		// because our len(ID) always 64
  		trie: patricia.NewTrie(patricia.MaxPrefixPerNode(64)),
  	}
  	for _, id := range ids {
  		idx.addID(id)
  	}
  	return
  }
docs: // NewTruncIndex creates a new TruncIndex and initializes with a list of IDs.