is it possible to provide an additional public API function for mongoc_collections to access the database, e.g. called  mongoc_collection_get_database()?

The need arose from trying to replace the deprecated function mongoc_collection_create_index() with the recommended interface based on mongoc_database_write_command_with_opts(), but this requires the db. The function has just the collection as input, so it would be appreciated to access the ->db member this way.