def notifyOnDisconnect(callback, *args, **kwargs):
    """Register a callback to run when we lose this connection.

        The callback will be invoked with whatever extra arguments you
        provide to this function. For example::

         def my_callback(name, number):
             print name, number+4
         cookie = rref.notifyOnDisconnect(my_callback, 'bob', number=3)

        This function returns an opaque cookie. If you want to cancel the
        notification, pass this same cookie back to dontNotifyOnDisconnect::

         rref.dontNotifyOnDisconnect(cookie)

        Note that if the Tub is shutdown (via stopService), all
        notifyOnDisconnect handlers are cancelled.
        """
