But if mentioning of C# invokes more that just musical associations for you, welcome to the realm of SDK, where things are not what they seem in user interface. As per SDK documentation:
With bulk deletion you can perform the following operations:… Delete data across multiple entities…
BulkDeleteRequest class contains a member variable QuerySet which, as the name suggests, is an array of QueryExpression objects.
If you ever spent time trying to make your bulk delete to run faster by modifying query page size, stop it. System duly ignores all your attempts and creates its own PageInfo object that processes 1,000 records batches.