Timezone-aware datetime

[diorcety]

Proposed change

Currently, the timestamp in the header extracted from reply is a timestamp without any timezone information. Is it recommanded to use timezone-aware object. The nats server sending the timestamp using UTC timezone we should use the following function: https://docs.python.org/3/library/datetime.html#datetime.datetime.fromtimestamp

Use case

Direct comptability with timezone away object

Contribution

No response