public PdfObjRef(PdfAnnotation annot, PdfStructElem parent, int nextStructParentIndex)
: base(new PdfDictionary(), parent)
{
annot.GetPdfObject().Put(PdfName.StructParent, new PdfNumber(nextStructParentIndex));
annot.SetModified();
PdfDictionary dict = (PdfDictionary)GetPdfObject();
dict.Put(PdfName.Type, PdfName.OBJR);
dict.Put(PdfName.Obj, annot.GetPdfObject());
}