JetStream Batch Get Client support

[mtmk]

Proposed change

ADR: https://github.com/nats-io/nats-architecture-and-design/blob/main/adr/ADR-31.md

Use case

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Contribution

No response

[Ivandemidov00]

Hi guys! I can try to solve this problem.
But I have some questions.
There is already ValueTask<NatsMsg<T>> GetDirectAsync<T>(StreamMsgGetRequest request,.... do I understand correctly that I will need to create a completely new method, for example IAsyncEnumerable<NatsMsg<T>> GetBatchDirectAsync<T>(StreamMsgBatchRequest request, ..... ?
Do I need to add support for .DIRECT.GET.{}.{} and multi_last in this request?

[mtmk]

thanks @Ivandemidov00 that would be great I think @scottf was going to work on it but not sure if he started

Edit
I talked to @scottf and he is not working on it at the moment so you can create a PR if you like.

will need to create a completely new method, for example IAsyncEnumerable<NatsMsg> GetBatchDirectAsync(StreamMsgBatchRequest request, ..... ?

Yes a new method like that looks good

Do I need to add support for .DIRECT.GET.{}.{} and multi_last in this request?

the details might change since server 2.11 still under development. which also means you'd need to develop against server main branch