Calls the given callback on the next IOLoop iteration.

        As of Tornado 6.0, this method is equivalent to `add_callback`.

        .. versionadded:: 4.0

def spawn_callback(self, callback: Callable, *args: Any, **kwargs: Any) -> None:
        """Calls the given callback on the next IOLoop iteration.

        As of Tornado 6.0, this method is equivalent to `add_callback`.

        .. versionadded:: 4.0
        """
        self.add_callback(callback, *args, **kwargs)