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 may block indefinitely and should not be used in user interface threads.
| this |
the secret collection |
| cancellable |
optional cancellation object |
|
whether the load was successful or not |