*   Changing `tf.data.experimental.save` to store the type specification of
        the dataset elements. This avoids the need for explicitly specifying the
        `element_spec` argument of `tf.data.experimental.load` when loading the
        previously saved dataset.
    *   Add `.element_spec` property to `tf.data.DatasetSpec` to access the
        inner spec. This can be used to extract the structure of nested