code: public void marshal(Object obj, HierarchicalStreamWriter writer,
  			MarshallingContext context) {
  		XTrace trace = (XTrace) obj;
  		writer.startNode("XAttributeMap");
  		context.convertAnother(trace.getAttributes(),
  				XesXStreamPersistency.attributeMapConverter);
  		writer.endNode();
  		for (XEvent event : trace) {
  			writer.startNode("XEvent");
  			context.convertAnother(event, XesXStreamPersistency.eventConverter);
  			writer.endNode();
  		}
  	}
docs: /*
  (non-Javadoc)
  
  @see
  com.thoughtworks.xstream.converters.Converter#marshal(java.lang.Object,
  com.thoughtworks.xstream.io.HierarchicalStreamWriter,
  com.thoughtworks.xstream.converters.MarshallingContext)