`tensorflow::tstring` which is now ABI stable.
*   A new Profiler for TF 2 for CPU/GPU/TPU. It offers both device and host
    performance analysis, including input pipeline and TF Ops. Optimization
    advisory is provided whenever possible. Please see
    [this tutorial](https://www.tensorflow.org/tensorboard/tensorboard_profiling_keras)
    and [guide](https://www.tensorflow.org/guide/profiler) for usage guidelines.