Can concurrence type be changed of NSPersistentDocument's managedObjectContext?

Question

I need the concurrence type of NSPersistentDocument's managedObjectContext to be NSMainQueueConcurrencyType because I need contexts in other threads.

Answer 1

Yes, you were right. Overriding manageObjectContext you can modify concurrency type. Maybe, I have some mistakes.

 - (NSManagedObjectContext *)managedObjectContext {
    __strong static NSManagedObjectContext *myManagedObjectContext = nil;

    if (myManagedObjectContext == nil) {
        myManagedObjectContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSMainQueueConcurrencyType];

        NSPersistentStoreCoordinator *psc = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]];
        [myManagedObjectContext setPersistentStoreCoordinator:psc];
    }

    return myManagedObjectContext;
}

Answer 2

The documentation for NSPersistentDocument says this about the managedObjectContext property:

If you want to customize the creation of the persistence stack, reimplement this property in your custom subclass and use your implementation to create the appropriate objects.

That seems pretty clear. Override this property and use whatever concurrency type you want. Have you tried it? Did it not work?