Transform document should be async

[Soremwar]

I want to extract the images from a document and replace the original image with a regular paragraph (which I can't do with convertImage), however transformDocument being sync is a big hurdle to extract the data from the image

Update: Using packages like deasync to read the image data synchronously hangs the process, so there is something at the core of it that just prevents an image from being read at transform time (but "convertion" time is ok)