*   Experimental support for shape invariants has been enabled in
        `tf.function`. See the API docs for
        `tf.autograph.experimental.set_loop_options` for additional info.
    *   AutoGraph error messages now exclude frames corresponding to APIs
        internal to AutoGraph.
    *   Improve shape inference for `tf.function` input arguments to unlock more
        Grappler optimizations in TensorFlow 2.x.