Motivation
The C driver does not support the batchSize option on the listCollections helper: mongoc_database_find_collections_with_opts.

The attachment includes a reproduction script. It is possible to pass a batch size to the initial listCollections command by passing option as the document: {cursor:{batchSize: 1}}.

However, any getMore command sent by the cursor when fetching more results does not use the same batchSize.

The Enumerate Collections specification does note this behavior is optional:

MAY allow the cursor.batchSize option to be passed.

Scope

Accept a batchSize as a top-level option, which applies to both the initial listCollections command and all getMore operations.