Prevent KeyValueStore error when MaxAge is set below the default DuplicateWindow value

[rickdotnet]

When setting a MaxAge less than the default DuplicateWindow value, you receive the following error. This PR fixes this.

NATS.Client.JetStream.NatsJSApiException: duplicates window can not be larger then max age
   at NATS.Client.JetStream.Internal.NatsJSResponse`1.EnsureSuccess() in C:\SourceControl\Random\nats.net.v2\src\NATS.Client.JetStream\Internal\NatsJSResponse.cs:line 27
   at NATS.Client.JetStream.NatsJSContext.JSRequestResponseAsync[TRequest,TResponse](String subject, TRequest request, CancellationToken cancellationToken) in C:\SourceControl\Random\nats.net.v2\src\NATS.Client.JetStream\NatsJSContext.cs:line 185
   at NATS.Client.JetStream.NatsJSContext.CreateStreamAsync(StreamConfig config, CancellationToken cancellationToken) in C:\SourceControl\Random\nats.net.v2\src\NATS.Client.JetStream\NatsJSContext.Streams.cs:line 21
   at NATS.Client.KeyValueStore.NatsKVContext.CreateStoreAsync(NatsKVConfig config, CancellationToken cancellationToken) in C:\SourceControl\Random\nats.net.v2\src\NATS.Client.KeyValueStore\NatsKVContext.cs:line 115
   at Program.<Main>$(String[] args) in C:\SourceControl\Random\nats.net.v2\sandbox\Example.KeyValueStore.Watcher\Program.cs:line 18
   at Program.<Main>(String[] args)

Modified Example.KeyValueStore.Watcher code to reproduce:

var nats = new NatsConnection();

var js = new NatsJSContext(nats);
var kv = new NatsKVContext(js);

var config = new NatsKVConfig("e1")
{
    MaxAge = TimeSpan.FromSeconds(30),
};

var store = await kv.CreateStoreAsync(config);

await foreach (var entry in store.WatchAsync<int>())
{
    Console.WriteLine($"[RCV] {entry}");
}

[mtmk]

Our general policy is not to fix validation issues but throw validation exception.

[rickdotnet]

Interesting. I wouldn't expect JS exceptions when operating with the K/V store. But, can fix on my end. No problem.

This would effectively limit MaxAge to >2min. Anything less than this would result in an error.

[mtmk]

I didn't mean to close the PR. it's a good use case. I think we should validate the config in kv.CreateStoreAsync(config) before sending it to the server. I personally like your approach but throwing an exception is our validation approach in NATS clients in general.

Edit: Apologies, you're right! 👇

[mtmk]

Actually what you've done seems to be the correct thing:

https://github.com/nats-io/nats.go/blob/98430acd80423b776149f29d625d158f490ac3c5/jetstream/kv.go#L334-L342

I didn't realised duplicate window wasn't actually part of KV config.

[mtmk]

LGTM thanks @rickdotnet 💯