code: public static String metricName(String type, String topologyId, String componentId, int taskId, String streamId, String group, String name) {
          return concat(type, topologyId, componentId, taskId, streamId, group, name);
      }
docs: a metric name composites of: type@topologyId@componentId@taskId@streamId@group@name for non-worker metrics
  OR type@topologyId@host@port@group@name for worker metrics