Add versions of KV commands that don't throw exceptions?

[darkwatchuk]

Proposed change

Add versions of KV commands that don't throw exceptions. Throwing exceptions in all cases when you're just interested in the outcome of an operation seems a bit overkill?

Use case

Some good uses for KV stores including leader election where we regularly try and get a lock on a resource. So a TryCreateAsync call where we get a bool might be better than calling CreateAsync and getting exceptions thrown constantly from the API. We may call this method every 1-3 seconds...

Likewise, just being interested in whether a kv pair exists or not might not need exceptions thrown all the time?

Contribution

Happy to look at this if can agree on the signatures...

[mtmk]

sounds reasonable to me. Once we establish a pattern we should potentially apply this to other JetStream APIs.