code: private void addQueryParams(final Request request) {
          if (recurring != null) {
              request.addQueryParam("Recurring", recurring.toString());
          }
  
          if (triggerBy != null) {
              request.addQueryParam("TriggerBy", triggerBy.toString());
          }
  
          if (usageCategory != null) {
              request.addQueryParam("UsageCategory", usageCategory.toString());
          }
  
          if (getPageSize() != null) {
              request.addQueryParam("PageSize", Integer.toString(getPageSize()));
          }
      }
docs: Add the requested query string arguments to the Request.
  
  @param request Request to add query string arguments to