Clarify whether Nats-Msg-Id should be globally unique or per-subject only

[nazar-pc]

I was wondering if Nats-Msg-Id should be globally unique or can be just unique within a specific subject, but wasn't able to find an answer.

It would be great if someone can clarify and update documentation around it.

[nazar-pc]

Friendly ping if someone is reading this

[nazar-pc]

Is there really nobody who knows this? 😅