Consider giving option to support binary formats like Protobuf

[oskardudycz]

That'd require a customisable outbox message data type to be either JSONB or BYTEA. See more:

#7 (comment)

[lsfera]

With jsonb we can assume the serialization format to be "application/json".
With bytea and binary formats things get a bit trickier and we might need to enrich the metadata storage with specific MIME type. E.g.: Bson/Protobuf