load_items

Ensure that the Collection proxy has loaded all the items present in the Secret Service.

This affects the result of [methodCollection.get_items].

For collections returned from [methodService.get_collections] the items will have already been loaded.

This method will return immediately and complete asynchronously.

Parameters:

this	the secret collection
cancellable	optional cancellation object
callback	called when the operation completes
user_data	data to be passed to the callback