Support OK message

[lubien]

From spec https://docs.nats.io/reference/reference-protocols/nats-protocol#protocol-messages

I've had to do a quick hack to support logs from Fly.io so maybe this is a good thing to add here too?

Would be glad to follow up with a PR

[mmmries]

A quick PR to support this message would greatly appreciated. I've never run this client against a nats server in verbose mode, but if that is useful to your use-case I can see how it would be useful for the whole community. Maybe we add a test where we start a nats server in verbose mode? That way we can make sure this functionality stays supported?

[lubien]

Sure, I can take a stab at it!