GCDRetainCycle6.m

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    self.proArray = [[NSMutableArray alloc]init];
    
    GCDVC2* __weak weakSelf = self;
    
    self.postGCDBlock = ^{

        GCDVC2* __strong strongSelf = weakSelf;

        [strongSelf.proArray removeObject:@"3"];
        NSLog(@"%@",strongSelf.proArray);
        [strongSelf.activityIndicator stopAnimating];
    };
    
    self.addObjectsBlock = ^{
        
        GCDVC2* __strong strongSelf = weakSelf;
        
        [strongSelf.proArray addObject:@"2"];
        [NSThread sleepForTimeInterval:10];
        
        dispatch_async(dispatch_get_main_queue(),strongSelf.postGCDBlock);
    };
}