[.Net][Feature Request]: Enable step-by-step execution for group chat using IAsyncEnumerable

[LittleLittleCloud]

Is your feature request related to a problem? Please describe.

developers might want to dive deep into the internal process of group chat for observation/early stop/etc..

Describe the solution you'd like

Provide an IAsyncEnumerable extension API to run group chat step by step.

public static class GroupChatExtension
{
    static IAsyncEnumeable<IMessage> SendAsync(IEnumerable<IMessage>? conversation = null, int maxRound = 10, CancellationToken ct = default);
}

Example: early stop when the message is from xxx

IGroupChat group;
await foreach (IMessage message in group.SendAsync(chatHistory))
{
      if (message.From == "xxx")
      {
            break;
      }
}

Additional context

No response