Comment 10 for bug 1628316

I'm starting to think that's not actually realistic to convert between the two classes since it'd just be copying some KSA Session instance attributes over to construct a SDK Session, which would maybe be close but likely flaky.

We have some overrides of the base KSA Session that we need in order to work as expected, like with endpoint selection, so I think we're going to have to need this to always be an SDK Session coming through. I think we can get what you need by just improving that from_config to generate the proper things coming out of os-client-config, whether they be from a YAML file or env vars.