Is there a way in Swift to export FileAttachment type annotations from a pdf using PDFKit?

Question

I have a need to export to file the FileAttachment type annotations of a pdf.

I am trying to use PDFKit but I cannot find a way to do this.

I'am able to filter annotations of type "FileAttachment" but I can't find any properties or methods that expose them to me in date format so I can save them to file.

I tried inspecting the properties and methods of the individual annotation but could not find the data format

import PDFKit

func filterFileAttachmentAnnotations(in pdfDocument: PDFDocument) -> [PDFAnnotation] {
    if let firstPage = pdfDocument.page(at: 0) {
       for annotation in firstPage.annotations {
            if annotation.type == "FileAttachment" {
                // HOWTO?: export fileattachment to user directory
                // annotation.contents is nil
                // annotation.url is nil
                // ...
            }
       }
    }
}