How to remember stream position when subscribing to kv watcher?

[CoenraadS]

Given the follow code, I can subscribe to a NATS KV Store

However each time the application starts, it will download all the data again. Since KV is an abstraction over a NATS stream, I'm hoping that I can somehow use a stream cursor to remember my position, but don't see how to do it via the api.

   await using var nc = new NatsClient(ADDRESS);
   
    var kv = nc.CreateKeyValueStoreContext();
    var profiles = await kv.CreateStoreAsync(new NatsKVConfig("profiles"));
   
    var watcher = Task.Run(async () =>
    {
        await foreach (var kve in profiles.WatchAsync<string>())
        {
            Console.WriteLine($"{kve.Key} @ {kve.Revision} -> {kve.Value} (op: {kve.Operation})");
        }
    });
   
    await watcher;

The behavior I want is that I would get latest revision of new keys (and also key deletions) since my last cursor position.

https://natsbyexample.com/examples/kv/intro/csharp

[Jarema]

Hey.

Server in fact can track progress through the stream, and that is done by a consumers, which can be durable and do live on the server.

However, watcher relies on ephemeral, short lived consumers which are discarded after watch is done.

In the client there should be options to start a watcher from a specific revision, or to get just the new entries, which could solve your issue. I encourage to discover the watcher starting point options, as it depends on the use case details.

I defer to @mtmk for more info and transfer the issue to .NET client, as it is purely client side topic.