Docs on MongoDB Atlas App Services function parameters

MongoDB Atlas App Services & Realm
1

For a MongoDB Atlas App Services function like:

exports = async function (payload, response) {
   const collection = context.services.get("mongodb-atlas")
                      .db("cards")
                      .collection("my collection");
...

Where can I find the parameters contents/docs, for payload and context?

Especially, if I want to get the http request, where can I get it?