public void updateHeartBeat() {
    lastHeartBeat.set(EnvironmentEdgeManager.currentTime());
    if (LOG.isDebugEnabled()) {
      LOG.debug("Heartbeat " + toString());
    }
  }
Updates timeout deadline for the lock.
hbase-server/src/main/java/org/apache/hadoop/hbase/master/locking/LockProcedure.java