code: func (t *treeNoder) NumChildren() (int, error) {
  	children, err := t.Children()
  	if err != nil {
  		return 0, err
  	}
  
  	return len(children), nil
  }
docs: // len(t.tree.Entries) != the number of elements walked by treewalker
  // for some reason because of empty directories, submodules, etc, so we
  // have to walk here.