code: func splitKey(key []byte) (id NodeID, field string) {
  	// If the key is not of a node, return it plainly
  	if !bytes.HasPrefix(key, nodeDBItemPrefix) {
  		return NodeID{}, string(key)
  	}
  	// Otherwise split the id and field
  	item := key[len(nodeDBItemPrefix):]
  	copy(id[:], item[:len(id)])
  	field = string(item[len(id):])
  
  	return id, field
  }
docs: // splitKey tries to split a database key into a node id and a field part.