assertTrue(task.isCancelled());
    assertEquals(1, runLatch.getCount());

    // Wait for the listeners to be called, don't rely on the same-thread exec.
    listenerLatch.await(5, SECONDS);
    assertTrue(task.isDone());
    assertTrue(task.isCancelled());

    // Make sure we didn't run anything.
    assertEquals(1, runLatch.getCount());
  }

    assertTrue(task.isCancelled());
    assertEquals(1, runLatch.getCount());

    // Wait for the listeners to be called, don't rely on the same-thread exec.
    listenerLatch.await(5, SECONDS);
    assertTrue(task.isDone());
    assertTrue(task.isCancelled());

    // Make sure we didn't run anything.
    assertEquals(1, runLatch.getCount());
  }

    *   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
        contention, via `tf.data.Options().experimental_slack = True`