objective-c - 为什么iOS的Masonry中的self不会循环引用?

Question

UIButton *testButton = [[UIButton alloc] init];
[self.view addSubview:testButton];
testButton.backgroundColor = [UIColor redColor];
[testButton mas_makeConstraints:^(MASConstraintMaker *make) {
    make.width.equalTo(@100);
    make.height.equalTo(@100);
    make.left.equalTo(self.view.mas_left);
    make.top.equalTo(self.view.mas_top);
}];
[testButton bk_addEventHandler:^(id sender) {
    [self dismissViewControllerAnimated:YES completion:nil];
} forControlEvents:UIControlEventTouchUpInside];

如果我用blocksKit的bk_addEventHandler方法, 其中使用strong self, 该viewController就无法dealloc, 我理解是因为,self retain self.view, retain testButton, retain self.
但是如果只用Mansonry的mas_makeConstraints方法, 同样使用strong self, 该viewController却能正常dealloc, 请问这是为什么, 为什么Masonry没有导致循环引用