Default Outline View Listener
class DefaultOutlineViewListener(pdfFragment: PdfFragment) : PdfOutlineView.OnOutlineElementTapListener, PdfOutlineView.OnAnnotationTapListener, PdfOutlineView.OnEmbeddedFileTapListener
Default implementation of OnOutlineElementTapListener, OnAnnotationTapListener, and OnEmbeddedFileTapListener to handle interactions with annotations and outline in PdfOutlineView.