code: func (f StructMap) GetByTraversal(index []int) *FieldInfo {
  	if len(index) == 0 {
  		return nil
  	}
  
  	tree := f.Tree
  	for _, i := range index {
  		if i >= len(tree.Children) || tree.Children[i] == nil {
  			return nil
  		}
  		tree = tree.Children[i]
  	}
  	return tree
  }
docs: // GetByTraversal returns a *FieldInfo for a given integer path.  It is
  // analogous to reflect.FieldByIndex, but using the cached traversal
  // rather than re-executing the reflect machinery each time.