@Override
  public void close() {
    if (!this.closed.compareAndSet(false, true)) {
      return;
    }
    // We could put back the chunks to pool for reusing only when there is no
    // opening scanner which will read their data
    this.refCnt.release();
  }
Close this instance since it won't be used any more, try to put the chunks back to pool
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/MemStoreLABImpl.java