gRPCClient的负载均衡器

public static Channel GetWorkingChannel(string key)
    {
      Ensure.NotNullOrEmpty(key);
      CachedItem item = null;
      _cacheMap.TryGetValue(key, out item);
      Channel currentChosenChannel = null;
      if (_cacheMap.IsNotEmpty())
      {
        foreach (var channel in item.Channels.OrderBy(o => Guid.NewGuid()))
        {
          try
          {
            if (channel.State == ChannelState.Idle || channel.State == ChannelState.Ready)
            {
              channel.ConnectAsync(DateTime.Now.AddMilliseconds(100)).Wait();
              currentChosenChannel = channel;
              break;
            }
          }
          catch
          {
            channel.ShutdownAsync().Wait();
          }
        };
      }

      if (currentChosenChannel == null) InitWorkingChannelsByKey(key);
      return currentChosenChannel;
    }

private static bool CheckIfConnectionIsWorking(Channel serverChannel)
    {
      if (serverChannel != null)
      {
        try
        {
          var client = new Health.HealthClient(serverChannel);
          var respOnse= client.Check(new HealthCheckRequest { Service = "HealthCheck" });
          return response.Status == HealthCheckResponse.Types.ServingStatus.Serving;
        }
        catch (Exception ex)
        {
          serverChannel.ShutdownAsync().Wait();
          return false;
        }
      }
      return false;
    }

 private static void ExecuteMaintenance(object state)
    {
      if (Interlocked.CompareExchange(ref _executing, 1, 0) != 0)
        return;
      try
      {
        if (_cacheMap.Count == 0)
        {
          StopMaintenance();
          if (_cacheMap.Count != 0)
            StartMaintenance();
        }
        else
        {
          DateTime oldThreshold = DateTime.UtcNow - _timeout;
          var expiredItems = _cacheMap.Where(i => i.Value.Updated  i.Key);
          for (int i = 0; i