RAC combineLatest:reduce: sample

gistfile1.m

    [[RACSignal combineLatest:@[connectUsersSignal, facebookUsersSignal, applicationUsersSignal] reduce:^id(NSArray *first, NSArray *second, NSArray *third) {
        return [[first arrayByAddingObjectsFromArray:second] arrayByAddingObjectsFromArray:third];
    }]
    subscribeNext:^(NSArray *allUsers) {
        //Do something
    }];