@Override
  public synchronized MetricsRegionServerSource
    createServer(MetricsRegionServerWrapper regionServerWrapper) {
    return new MetricsRegionServerSourceImpl(regionServerWrapper);
  }
Factory to create MetricsRegionServerSource when given a MetricsRegionServerWrapper
hbase-hadoop-compat/src/main/java/org/apache/hadoop/hbase/regionserver/MetricsRegionServerSourceFactoryImpl.java