code: private SenderConfiguration validateAndSanitizeConfiguration(VariantType type, SenderConfiguration configuration) {
          switch (type) {
              case ANDROID:
                  if (configuration.batchSize() > 1000) {
                      logger.warn(String
                              .format("Sender configuration -D%s=%s is invalid: at most 1000 tokens can be submitted to GCM in one batch",
                                      getSystemPropertyName(type, ConfigurationProperty.batchSize), configuration.batchSize()));
                      configuration.setBatchSize(1000);
                  }
                  break;
              default:
                  break;
          }
          return configuration;
      }
docs: Validates that configuration is correct with regards to push networks limitations or implementation, etc.