LazyLoader.m

@interface View : UIView

@property (nonatomic, weak) UIView *mySubview;

@end

@implementation View

- (UIView *)mySubview {
  if (!_mySubview) {
    UIView *v = [[UIView alloc] initWithFrame:CGRectZero];
    
    ... some setup
    
    _mySubview = v;
    [self addSubview:v];
  }
  return _mySubview;
}

@end