docs: public static Element writeRoadSegment(RoadSegment primitive, XMLBuilder builder, XMLResources resources) throws IOException {
  		if (primitive instanceof RoadPolyline) {
  			return writeRoadPolyline((RoadPolyline) primitive, builder, resources);
  		}
  		throw new IOException("unsupported type of primitive: " + primitive); //$NON-NLS-1$
  	}