/** {@inheritDoc} */
  @Override
  public void autoFlushFrequency(long autoFlushFreq) {
    A.ensure(autoFlushFreq >= 0, "autoFlushFreq >= 0");

    long old = this.autoFlushFreq;

    if (autoFlushFreq != old) {
      this.autoFlushFreq = autoFlushFreq;

      if (autoFlushFreq != 0 && old == 0) flushQ.add(this);
      else if (autoFlushFreq == 0) flushQ.remove(this);
    }
  }
  /** {@inheritDoc} */
  @Override
  public void perNodeBufferSize(int bufSize) {
    A.ensure(bufSize > 0, "bufSize > 0");

    this.bufSize = bufSize;
  }