Using ReactiveCoreData with NSBlockOperation

gistfile1.txt

    NSBlockOperation *operation = [NSBlockOperation blockOperationWithBlock:^{
        [[[RACSignal startEagerlyWithScheduler:[RACScheduler scheduler] block:^(id <RACSubscriber> subscriber) {
            NSManagedObjectContext *context = [NSManagedObjectContext contextWithMainContext:self.managedObjectContext];    // self is AppDelegate
            [context attachToCurrentScheduler];
            [subscriber sendNext:nil];
            [subscriber sendCompleted];
        }] saveContext] subscribeCompleted:^{
            NSLog(@"Completed");
        }];
    }];