vim-foldtext

Credit

Thanks to https://github.com/scottmcginness/vim-foldtext for the original code base this foldtext routine began from.

Use your preferred plugin manager to install

Respects indent level
Handles dynamic toggling of sign/fold/number columns
Line count info can be toggled with let g:FoldText_info=!g:FoldText_info
Use indentLine for fold-line shown in example as an alternative to foldcolumn lines