ios – detect Web page Change solely throughout the ThumnailView (however not pay attention PDFPageView Change)

I’ve a PDFThumbnailView that’s used with a PageViewController (That host a PDFView as a subview).

For a really particular case, I want to detect any Index Change from PDFThumbnailView as a way to change the PageViewController accordingly.

I’m conscious that when PDFThumbnailView is linked to a PDFView we are able to pay attention to Notifications from PDFView Web page Modifications, however this isn’t what I need. I simply need an occasion from PDFThumbnailView. The aim is to make use of that for actioning one thing exterior PDFView.

I attempted to make use of Mix or Basic Observer to look at any property from PDFThumbnailView however none appear to work.

     let commentary = observe(
            .pdfThumbnailView.selectedPages, // or another property
                  choices: [.old, .new]
          ) { object, change in
               print("new change: (change.oldValue?.debugDescription ?? ""), up to date to: (change.newValue?.debugDescription ?? "")")
}

Is there a option to observe web page index change throughout the PDFThumbnailView (and never wait any PDFView linked PDFThumbnailView to get the Web page Occasion)?

I did search a bit in all places, however no outcome up to now.