fun start()
  }

  private object TestThreadSerialTask : SerialTask {
    override fun start() = error("unexpected call")
  }

  inner class RunnableSerialTask(
    private val runnable: Runnable,
  ) : SerialTask {
    override fun start() {
      taskRunner.assertThreadHoldsLock()
      require(currentTask == this)
      activeThreads++

   * smaller). For example, partitioning an iterator containing {@code [a, b, c, d, e]} with a
   * partition size of 3 yields {@code [[a, b, c], [d, e]]} -- an outer iterator containing two
   * inner lists of three and two elements, all in the original order.
   *
   * <p>The returned lists implement {@link java.util.RandomAccess}.
   *

        `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
        datasets.
    *   Add `tf.data.experimental.AutoShardingPolicy.HINT` which can be used to