@Override
  public QueueStatHelper getSerialQueueHelper() {
    return new QueueStatHelper() {
      @Override
      public void add() {
        incSerialQueueSize(1);
      }

      @Override
      public void remove() {
        incSerialQueueSize(-1);
      }

      @Override
      public void remove(long count) {
        incSerialQueueSize(-count);
      }
    };
  }
Returns a helper object so that the serial queue can record its stats to the proper
distribution stats.

@since GemFire 3.5
geode-core/src/main/java/org/apache/geode/distributed/internal/locks/DLockStats.java