This is what I'm going to be digging for later... I'm wondering if puma also shares `env` objects across requests.
https://github.com/puma/puma/blob/0cc3f7d71d1550dfa8f545ece8...
and Client objects are not reused:
https://github.com/puma/puma/blob/0cc3f7d71d1550dfa8f545ece8...