PDFview scrolls to bottom of the page in single page document

I propose this solution for scrolling to top of first page (it works on iOS 11.3):

if let document = pdfView.document,
   let firstPage = document.page(at: 0)
{
    let firstPageBounds = firstPage.bounds(for: pdfView.displayBox)
    pdfView.go(to: CGRect(x: 0, y: firstPageBounds.height, width: 1.0, height: 1.0), on: firstPage)
}

This is what I did, it's a bit hacky

if let scrollView = pdfView.subviews.first as? UIScrollView {
    scrollView.contentOffset.y = 0.0
}

I think this is a bug in PDFView.

As workaround I suggest to manually scroll top the top:

self.pdfView.document = pdfDocument;

NSPoint pt = NSMakePoint(0.0, [self.pdfView.documentView bounds].size.height);
[self.pdfView.documentView scrollPoint:pt];

Bug Reporter

rdar://37942090: PDFview scrolls to bottom of the page in single page document.