code: private void validate() {
          LibraryUtils.checkArgumentNotNull(config, "configuration is null");
          LibraryUtils.checkArgumentNotNull(exceptionHandler, "exceptionHandler is null");
          LibraryUtils.checkArgumentNotNull(progressReporter, "progressReporter is null");
          LibraryUtils.checkArgumentNotNull(s3Client, "s3Client is null");
      }
docs: Validates input parameters.