How to get index of contentChild List?

how to get index of content child list ?

contentChild: (context, value) {)

[gbbest15]

check my fork repo

if is what u like star the forked

 comment_tree:
    git:
      url: https://github.com/gbbest15/flutterCommentTree.git
      ref: master

@gbbest15 not getting the index of content child list?