public override void Invoke(AWSCredentials creds, RegionEndpoint region, int maxItems)
        {
            AmazonIdentityManagementServiceConfig config = new AmazonIdentityManagementServiceConfig();

            config.RegionEndpoint = region;
            ConfigureClient(config);
            AmazonIdentityManagementServiceClient client = new AmazonIdentityManagementServiceClient(creds, config);


            ListSigningCertificatesResponse resp = new ListSigningCertificatesResponse();

            do
            {
                ListSigningCertificatesRequest req = new ListSigningCertificatesRequest
                {
                    Marker = resp.Marker
                    ,
                    MaxItems = maxItems
                };

                resp = client.ListSigningCertificates(req);
                CheckError(resp.HttpStatusCode, "200");

                foreach (var obj in resp.Certificates)
                {
                    AddObject(obj);
                }
            }while (!string.IsNullOrEmpty(resp.Marker));
        }
 public Task <ListSigningCertificatesResponse> ListSigningCertificatesAsync(ListSigningCertificatesRequest request,
                                                                            CancellationToken cancellationToken = new CancellationToken())
 {
     throw new System.NotImplementedException();
 }