How to emulate vim job out_io buffer with neovim?

Question

I'd like to make a plugin with functionality that is similar to https://github.com/ramele/agrep and grep-edit in emacs. That is get search results from ag or some other tool that supports multiline matches (otherwise quickfix and cdo is just as good choice I think), colorise them and group by file (ag do this by default) and then basically mirror any changes made in this buffer to the actual files.