private void clearZKExceptionMetrics() {
    // Reset the exception metrics.
    clearMetricIfNotNull(authFailedFailedOpCount);
    clearMetricIfNotNull(connectionLossFailedOpCount);
    clearMetricIfNotNull(dataInconsistencyFailedOpCount);
    clearMetricIfNotNull(invalidACLFailedOpCount);
    clearMetricIfNotNull(noAuthFailedOpCount);
    clearMetricIfNotNull(operationTimeOutFailedOpCount);
    clearMetricIfNotNull(runtimeInconsistencyFailedOpCount);
    clearMetricIfNotNull(sessionExpiredFailedOpCount);
    clearMetricIfNotNull(systemErrorFailedOpCount);
    clearMetricIfNotNull(totalFailedZKCalls);
  }
Class that transitions metrics from MetricsZooKeeper into the metrics subsystem. Implements
BaseSource through BaseSourceImpl, following the pattern.
hbase-hadoop-compat/src/main/java/org/apache/hadoop/hbase/zookeeper/MetricsZooKeeperSourceImpl.java