public static List<alluxio.grpc.Metric> reportClientMetrics() {
    long start = System.currentTimeMillis();
    List<alluxio.grpc.Metric> metricsList = reportMetrics(InstanceType.CLIENT);
    LOG.debug("Get the client metrics list contains {} metrics to report to leading master in {}ms",
        metricsList.size(), System.currentTimeMillis() - start);
    return metricsList;
  }
@Test
  public void testReportClientMetrics() {
    String metricName = "Client.TestMetric";
    Counter counter = MetricsSystem.counter(metricName);
    if (!MetricKey.isValid(metricName)) {
      MetricKey.register(new MetricKey.Builder(metricName)
          .setMetricType(MetricType.COUNTER).setIsClusterAggregated(true).build());
    }
    counter.inc(5);
    assertEquals(5.0, MetricsSystem.reportClientMetrics().get(0).getValue(), 0);
    assertEquals(0, MetricsSystem.reportClientMetrics().size());
    counter.inc(2);
    assertEquals(2.0, MetricsSystem.reportClientMetrics().get(0).getValue(), 0);
    assertEquals(0, MetricsSystem.reportClientMetrics().size());
  }