@Override
  public void setGauge(String gaugeName, long value) {
    MutableGaugeLong gaugeInt = metricsRegistry.getGauge(gaugeName, value);
    gaugeInt.set(value);
  }
Set a single gauge to a value.
@param gaugeName gauge name
@param value     the new value of the gauge.
hbase-hadoop-compat/src/main/java/org/apache/hadoop/hbase/metrics/BaseSourceImpl.java