and `tf.contrib.estimator.make_stop_at_checkpoint_step_hook` with
        `tf.estimator.experimental.InMemoryEvaluatorHook` and
        `tf.estimator.experimental.make_stop_at_checkpoint_step_hook`
    *   Migrate linear optimizer from contrib to core.

## Thanks to our Contributors

This release contains contributions from many people at Google, as well as: