确定订阅的哪个 GRPC 服务已关闭 .NET 7

问：

我有这个用于订阅 GRPC 流服务的实现，但是，我必须确定其中一个服务何时关闭并调用事件以通知 UI。

public async Task Subscribe()
{
     await Policy
          .Handle<RpcException>(e => e.Status.StatusCode == StatusCode.Unavailable)
          .WaitAndRetryAsync(
                    10,
                    attempt => TimeSpan.FromSeconds(Math.Pow(2, attempt)),
                    onRetry: (e, ts) => {
                        logger.Warning("Subscription connection lost. Trying to reconnect in {Seconds}s!", ts.Seconds);

                    })
          .ExecuteAsync(() => {
               IAsyncEnumerable<Notification> stream = await subscribe.Subscribe(currentUser)
               await foreach (Notification? ev in stream)
               {
                    switch (reply.ActionCase)
                    {
                        case Notification.ActionOneofCase.Service1:
                            logger.Warning("Incoming reply 'Service1'");
                            break;

                        case Notification.ActionOneofCase.Service2:
                            //TODO:
                            break;
                    }
            }
     });
}

我尝试使用polly，但我不知道如何在一个特定服务关闭时获取。我需要确定其中一个服务何时关闭以通知 UI。识别哪个服务关闭的最佳方法是什么？

编辑：

这就是每个服务的注入方式：

private static void AddGrpcService<T>(IServiceCollection services,
                                        Config config) where T : class
{
    SocketsHttpHandler socketsHandler = new SocketsHttpHandler()
    {
        PooledConnectionIdleTimeout = Timeout.InfiniteTimeSpan,
        KeepAlivePingDelay = TimeSpan.FromSeconds(60),
        KeepAlivePingTimeout = TimeSpan.FromSeconds(30),
        EnableMultipleHttp2Connections = true
    };

    MethodConfig defaultMethodConfig = new MethodConfig
    {
        Names = { MethodName.Default },
        RetryPolicy = new RetryPolicy
        {
            MaxAttempts = 5,
            InitialBackoff = TimeSpan.FromSeconds(1),
            MaxBackoff = TimeSpan.FromSeconds(5),
            BackoffMultiplier = 1.5,
            RetryableStatusCodes = { StatusCode.Unavailable }
        }
    };

    ServiceConfig serviceConfig = new() { MethodConfigs = { defaultMethodConfig } };
    services.AddGrpcClient<T>(o => {
        o.Address = new Uri(config.GrpcUrl);
    })
            .ConfigureChannel(o => {
                o.Credentials = GetGrpcClientCredentials(config);
                o.ServiceConfig = serviceConfig;
            })
            .ConfigurePrimaryHttpMessageHandler(() => socketsHandler);
}