*   `tf.data`:
    *   `tf.data.Dataset`
    *   Add support for building C++ Dataset op kernels as external libraries,
        using the `tf.load_op_library()` mechanism.
    *   `Dataset.list_files()` now shuffles its output by default.
    *   `Dataset.shuffle(..., seed=tf.constant(0, dtype=tf.int64))` now yields
        the same sequence of elements as `Dataset.shuffle(..., seed=0)`.