Setting contentInset of scrollView makes it jump

scrollViewJumpsWhenSettingContentIset.m

The cause of this problem is when the contentInset is set, contentOffset is also set to a value according to the new value of contentInset. 
So restore contentOffset to its old value after setting contentInset solves the problem. 
It seems the animation block is not needed in my app with iOS 9.0.

- (void)setLoadingScrollViewInsets:(UIScrollView *)scrollView
{
    UIEdgeInsets loadingInset = scrollView.contentInset;
    loadingInset.top += self.view.frame.size.height;

    CGPoint contentOffset = scrollView.contentOffset;

    [UIView animateWithDuration:0.2 animations:^
    {
        scrollView.contentInset = loadingInset;
        scrollView.contentOffset = contentOffset;
    }];
}