private long getGaugeValue(String suffix) {
    return (long) gauges.get(HelixClusterManager.class.getName() + "." + suffix).getValue();
  }
Get the gauge value for the metric in {@link HelixClusterManagerMetrics} with the given suffix.
@param suffix the suffix of the metric that distinguishes it from other metrics in the class.
@return the value of the gauge.
ambry-clustermap/src/test/java/com/github/ambry/clustermap/HelixClusterManagerTest.java