@Override
  public void init() {
    this.metricsRegistry.clearMetrics();
  }
The adapter from hbase-metrics module to metrics2. This adepter is the connection between the
Metrics in the MetricRegistry and the Hadoop Metrics2 system. Using this adapter, existing
BaseSource implementations can define new metrics using the hbase-metrics/hbase-metrics-api
module interfaces and still be able to make use of metrics2 sinks (including JMX). Existing
BaseSources should call metricsAdapter.snapshotAllMetrics() in getMetrics() method. See
{@link MetricsRegionServerSourceImpl}.
hbase-hadoop-compat/src/main/java/org/apache/hadoop/hbase/metrics/BaseSourceImpl.java