Problem getting contentInset from RefreshView.

[HyunjoonKo]

In the case of the contentInsetTop and contentInsetBottom variables of RefreshView, the value of contentInset and the value of adjustedContentInset are added.

However, this results in the same result as multiplying contentInset twice.
Because the value of adjustedContentInset is contentInset plus the value of safeArea.

The following fixes the problem where the scroll view is strange after refreshing or the value of contentOffset that is necessary for refreshing is too large:

private extension UIScrollView {
    var contentInsetTop: CGFloat {
        if #available(iOS 11.0, *) {
            return adjustedContentInset.top
        } else {
            return contentInset.top
        }

        return contentInset.top
    }

    var contentInsetBottom: CGFloat {
        if #available(iOS 11.0, *) {
            return adjustedContentInset.bottom
        } else {
            return contentInset.bottom
        }
    }
}