message: ellaborated docs on determinism in dataset ops
diff: @@ -1774,6 +1774,11 @@ name=None))
  in general precludes the possibility of executing user-defined
  transformations in parallel (because of Python GIL).
  + The order of elements yielded by this transformation is
  + deterministic, as long as `map_func` is a pure function and
  + `deterministic=True`. If `map_func` contains any stateful operations, the
  + order in which that state is accessed is undefined.
  +
  Performance can often be improved by setting `num_parallel_calls` so that
  `map` will use multiple threads to process elements. If deterministic order
  isn't required, it can also improve performance to set
  @@ -1792,11 +1797,10 @@ name=None))
  `tf.data.AUTOTUNE` is used, then the number of parallel
  calls is set dynamically based on available CPU.
  deterministic: (Optional.) A boolean controlling whether determinism
  - should be traded for performance by allowing elements to be produced out
  + should be traded for performance by allowing elements to be yielded out
  of order. If `deterministic` is `None`, the
  `tf.data.Options.experimental_deterministic` dataset option (`True` by
  - default) is used to decide whether to produce elements
  - deterministically.
  + default) is used to decide whether to run deterministically.
  Returns:
  Dataset: A `Dataset`.
  @@ -1925,8 +1929,7 @@ name=None))
  should be traded for performance by allowing elements to be produced out
  of order. If `deterministic` is `None`, the
  `tf.data.Options.experimental_deterministic` dataset option (`True` by
  - default) is used to decide whether to produce elements
  - deterministically.
  + default) is used to decide whether to run deterministically.
  Returns:
  Dataset: A `Dataset`.
  