Can we make Hash support parallel reads and writes, be thread-safe, and still be as fast on a single thread as before? Yes! With extensive state-of-the-art research, including an all-new lock to allow parallel reads and writes, we found a way to achieve all of these goals. Embark on a journey to reimplement Hash so it’s fast and safe no matter if used by one or many threads at once. It's even safer than under the GVL!