@Override
  public Lock readLock() {
    return readLock;
  }
Creates a new monitoring wrapper around a R/W lock.
The so created wrapper instance can be used instead of the original R/W
lock, which then automatically updates the monitoring values in the <code>
MetricsSource</code>. This allows easy "slide in" of lock monitoring where
originally only a standard R/W lock was used.

@param lock The original R/W lock to wrap for monitoring
@param metrics The target for lock monitoring
llap-common/src/java/org/apache/hadoop/hive/llap/metrics/ReadWriteLockMetrics.java