kMDQueryProgressNotification
Indicates that a query’s results list has change during the initial result-gathering phase of a query.
Overview
New items are typically added during this phase, however it is possible for items to be removed or updated, if the original file is changed. The info dictionary of the notification can contain kMDQueryUpdateChangedItems and kMDQueryUpdateRemovedItems keys.
For performance reasons added results are not indicated in progress notifications, to avoid the cost of creating the result objects.
This notification is only sent to the application’s notification center.