PDFKit Link Annotations gets stripped off when saving

I'm using the following code to draw a text over PDF page.Everything works fine, but if you process a PDF with internal links eg: a Book with Content links to pages, the resultant PDF file seems to have the links stripped off.Why does this happen?

                let data = NSMutableData()
                let consumer = CGDataConsumer(data: data as CFMutableData)!
                let context = CGContext(consumer: consumer, mediaBox: nil, nil)!
                let pdffile=PDFDocument(url: input)                   
                for y in stride(from: 0, to: pagecount, by: 1)
                {
                let page: PDFPage = pdffile!.page(at: y)!
                var mediaBox = page.bounds(for: PDFDisplayBox.mediaBox)
                NSGraphicsContext.current = NSGraphicsContext(cgContext: context, flipped: false)
                
                let bounds = page.bounds(for: PDFDisplayBox.mediaBox)
                let size = bounds.size                   
                page.draw(with: .mediaBox, to: context)
                text.draw(in:drawrect,withAttributes:textFontAttributes);
                context.endPDFPage()
                }
                context.closePDF()
                try! data!.write(to: GetOutputFileName(inputfile: x), options[.atomicWrite])

What I have tried is saving the annotation of each page applying it before ending the page

               for annotation in pageannottaions
                {
                    page.addAnnotation(annotation)
                }

This also does not work.Please advice