observeChanges on a grapher query

[Floriferous]

We'd like to subscribe to data on the client, that is basically postprocessed mongo documents, in our case a PDF, made out of data from our DB.

We'd like the server to publish a live version of this PDF, as a string, so we can render it on the client, reactively, as we edit the data from the frontend.

A way to do this would be to create a custom publication function that uses the low-level added changed removed API, and send the PDF as a string to the client, but I'm not sure if that's doable?

The issue is I'd like to subscribe to a grapher query with nested, linked, documents.