code: private void formatResultMessage(final Metric pluginMetric) {
          if (StringUtils.isEmpty(pluginMetric.getMessage())) {
              return;
          }
  
          if (StringUtils.isEmpty(retValMessage)) {
              retValMessage = pluginMetric.getMessage();
              return;
          }
          retValMessage += " " + pluginMetric.getMessage();
      }
docs: Formats the message to return to Nagios according to the specifications
  contained inside the pluginMetric object.
  
  @param pluginMetric
  The metric.