}

    private long writeTime = Long.MAX_VALUE;

    @Override
    public long getWriteTime() {
      return writeTime;
    }

    @Override
    public void setWriteTime(long time) {
      this.writeTime = time;
    }

    private ReferenceEntry<K, V> nextWrite = nullEntry();

    @Override
    public ReferenceEntry<K, V> getNextInWriteQueue() {