Adds a weak reference callback to a mini object. Weak references are
used for notification when a mini object is finalized. They are called
"weak references" because they allow you to safely hold a pointer
to the mini object without calling MiniObject.ref
(MiniObject.ref adds a strong reference, that is, forces the object
to stay alive).
Adds a weak reference callback to a mini object. Weak references are used for notification when a mini object is finalized. They are called "weak references" because they allow you to safely hold a pointer to the mini object without calling MiniObject.ref (MiniObject.ref adds a strong reference, that is, forces the object to stay alive).