import { GridFSBucket } from "https://deno.land/x/model@v1.2/dependencies/mongo.ts";
Uploads a user file to a GridFS bucket. The application supplies a custom file id.
Reads the contents of the user file from the @source Stream and uploads it as chunks in the chunks collection. After all the chunks have been uploaded, it creates a files collection document for @filename in the files collection.
Note: there is no need to return the id of the uploaded file because the application already supplied it as a parameter.