Decrements the reference count for the type corresponding to the
interface default vtable g_iface.
If the type is dynamic, then when no one is using the interface and all
references have been released, the finalize function for the interface's
default vtable (the class_finalize member of GObject.TypeInfo) will be called.
Decrements the reference count for the type corresponding to the interface default vtable
g_iface.If the type is dynamic, then when no one is using the interface and all references have been released, the finalize function for the interface's default vtable (the
class_finalizemember of GObject.TypeInfo) will be called.