code: func (s *GlobalStore) nodeKeyIndex(addr common.Address, key []byte) (index int, found bool) {
  	l := len(s.nodeKeys[addr])
  	index = sort.Search(l, func(i int) bool {
  		return bytes.Compare(s.nodeKeys[addr][i], key) >= 0
  	})
  	found = index < l && bytes.Equal(s.nodeKeys[addr][index], key)
  	return index, found
  }
docs: // nodeKeyIndex returns the index of a key in nodeKeys slice.