Congratulations to the authors, this was a feature that was dearly missing from pyca/cryptography. It took a long time to get right.
For the history: https://github.com/pyca/cryptography/issues/2381
For the history: https://github.com/pyca/cryptography/issues/2381
That's not to say this is done! There's a set of features we still want to add and we'd like to gain some confidence in the APIs as structured before we mark them as stabilized.