RegistrationBag.~this

Destroy this bag, detaching all live registrations.

Finalizer caveat: this destructor touches other GC-managed objects (the anchored registrations and their hap states). It is reliable for stack-allocated, struct-member and explicitly destroyed owners; for owners collected by the GC as class instances, the D specification does not guarantee that referenced objects are still valid during finalization. Call clear() at a deterministic lifecycle point and treat this destructor as a best-effort backstop.