Adjust text before rendering

I really love this project but I have a minor issue.
I usually add some metadata to my markdown files (e.g. tags, date...) that I would like to filter out from the preview.
I was looking at your code hoping to find a sport where I can hook into and remove those lines from the text before it is rendered.
Any suggestions for where to look? Perhaps in this [function](https://github.com/iamcco/markdown-preview.nvim/blob/5a35462650e6c6b99143a15b76d6328266317a62/autoload/mkdp/nvim/api.vim#L155)? (assuming that is where the ts server reads the buffer from)