code: private void onPopLevelProgress(Object source)
      {
          DefaultJobProgressStep parent = this.currentStep.getParent();
  
          if (parent == null) {
              LOGGER.warn("PopLevelProgressEvent was fired too many times. Don't forget "
                  + "to match each PopLevelProgressEvent with a PushLevelProgressEvent.");
  
              return;
          }
  
          // Try to find the right level based on the source
          DefaultJobProgressStep level = findLevel(this.currentStep.getParent(), source);
  
          if (level == null) {
              LOGGER.warn("Could not find any matching step level for source [{}]. Ignoring PopLevelProgressEvent.",
                  source.toString());
  
              return;
          }
  
          // Move to parent step
          this.currentStep = level;
  
          // Close the level
          this.currentStep.finishLevel();
      }
docs: Called when a {@link PopLevelProgressEvent} is fired.