code: public Page<Metric> listMetrics() {
      // [START listMetrics]
      Page<Metric> metrics = logging.listMetrics(ListOption.pageSize(100));
      for (Metric metric : metrics.iterateAll()) {
        // do something with the metric
      }
      // [END listMetrics]
      return metrics;
    }
docs: [TARGET listMetrics(ListOption...)]