code: private void validate() {
          LibraryUtils.checkArgumentNotNull(config, "configuration is null");
          LibraryUtils.checkArgumentNotNull(exceptionHandler, "exceptionHandler is null");
          LibraryUtils.checkArgumentNotNull(progressReporter, "progressReporter is null");
          LibraryUtils.checkArgumentNotNull(sqsClient, "sqsClient is null");
          LibraryUtils.checkArgumentNotNull(sourceSerializer, "sourceSerializer is null");
      }
docs: Convenient function to validate input.