AmazonBedrockAgentRuntimeClient.RetrieveAndGenerateAsync throws an exception about aws-sdk-net HOT 4 CLOSED

....
    Console.WriteLine("Please enter the Knowledge Base Id");

    string? kbId = Console.ReadLine();

    Console.WriteLine("Please enter your first prompt, after this type exit to stop prompting bedrock.");

    var input = Console.ReadLine();

    var sessionId = "";
    while (input?.ToUpperInvariant() != "EXIT")
    {    
        var response = await InvokeBedrockRetrieveAndGenerateKnowledgeBaseAsync(kbId, input, sessionId);

        if (response != null)
        {
            Console.WriteLine(response.Output.Text);

            sessionId = response.SessionId;
        }
        else
        {
            Console.WriteLine("Error Occurred");
        }

        Console.WriteLine("Please write your next prompt or type exit to leave.");
        input = Console.ReadLine();
    }
.....
  public static async Task<RetrieveAndGenerateResponse> InvokeBedrockRetrieveAndGenerateKnowledgeBaseAsync(string knowledgeBaseId, string prompt, string sessionId = "")
  {
      RetrieveAndGenerateResponse? result = null;
      try
      {
          AmazonBedrockAgentRuntimeClient client = new(RegionEndpoint.USEast1);

          Console.WriteLine($"Calling bedrock with Knowledge Base Id: {knowledgeBaseId}, prompt: {prompt} and {(String.IsNullOrWhiteSpace(sessionId) ? "No session Id" : $"Session Id: {sessionId}")}.");

          var request = new RetrieveAndGenerateRequest
          {
              Input = new RetrieveAndGenerateInput
              {
                  Text = prompt
              },
              RetrieveAndGenerateConfiguration = new RetrieveAndGenerateConfiguration
              {
                  Type = "KNOWLEDGE_BASE",
                  KnowledgeBaseConfiguration = new KnowledgeBaseRetrieveAndGenerateConfiguration
                  {
                      KnowledgeBaseId = knowledgeBaseId,
                      ModelArn = "arn:aws:bedrock:us-east-1::foundation-model/anthropic.claude-v2",
                  }
              },
          };

          if (!String.IsNullOrWhiteSpace(sessionId))
              request.SessionId = sessionId;

          RetrieveAndGenerateResponse response = await client.RetrieveAndGenerateAsync(request);
          
          if (response.HttpStatusCode == System.Net.HttpStatusCode.OK)
          {
              result = response;
          }
          else
          {
              Console.WriteLine("InvokeModelAsync failed with status code " + response.HttpStatusCode);
          }
      }
      catch (Exception ex)
      {
          Console.WriteLine(ex.ToString());
      }

      return result;
  }