docs: private void addPrimaryLayer() {
      LineLayer primary = TrafficLayer.getLineLayer(
        Primary.BASE_LAYER_ID,
        Primary.ZOOM_LEVEL,
        Primary.FILTER,
        Primary.FUNCTION_LINE_COLOR,
        Primary.FUNCTION_LINE_WIDTH,
        Primary.FUNCTION_LINE_OFFSET
      );
  
      LineLayer primaryCase = TrafficLayer.getLineLayer(
        Primary.CASE_LAYER_ID,
        Primary.ZOOM_LEVEL,
        Primary.FILTER,
        Primary.FUNCTION_LINE_COLOR_CASE,
        Primary.FUNCTION_LINE_WIDTH_CASE,
        Primary.FUNCTION_LINE_OFFSET,
        Primary.FUNCTION_LINE_OPACITY_CASE
      );
  
      addTrafficLayersToMap(primaryCase, primary, getLastAddedLayerId());
    }