Introduces an extension to the aggregation operator $convert to allow any Object to be converted to BinData containing its BSON binary representation. The primary motivation is enabling byte-level comparison of documents during migration verification (see SERVER-104650).

Description of Linked Ticket

It would be useful, in tandem with planned hashing functionality, to be able to transform arbitrary objects in aggregation to their BSON representation.

It would work something like this:

{ $convert: {
    input: { foo: "bar" },
    to: "binData",
    format: "bson",
}}