*   Add support for defaulting the value of `cycle_length` argument of
        `tf.data.Dataset.interleave` to the number of schedulable CPU cores.
    *   Promoting `tf.data.experimental.enumerate_dataset` to core as
        `tf.data.Dataset.enumerate`.
    *   Promoting `tf.data.experimental.unbatch` to core as
        `tf.data.Dataset.unbatch`.
    *   Adds option for introducing slack in the pipeline to reduce CPU