*   Add support for TensorArrays to `tf.data Dataset`.
    *   Integrate Ragged Tensors with `tf.data`.
    *   All core and experimental tf.data transformations that input
        user-defined functions can span multiple devices now.
    *   Extending the TF 2.0 support for `shuffle(...,
        reshuffle_each_iteration=True)` and `cache()` to work across different
        Python iterators for the same dataset.