Gets or sets the destination shown when the item is activated (Dest), or null.
public PdfDestination? Destination { get; set; }
ISO 32000-2 §12.3.3, Table 151, and §12.3.2: an explicit destination, or a named one (a name or a string). Setting a destination
writes its array or name as Dest and removes any A ("shall not be present if a Dest entry is present"); setting
null removes Dest. Make destinations with CreateDestination(PdfPage, PdfDestinationView, Nullable<Double>, Nullable<Double>, Nullable<Double>, Nullable<Double>, Nullable<Double>) or
SetNamedDestination(String, PdfExplicitDestination).