@Override
  public void close() {
    if (closed) return;
    cur = null;
    this.hfs.close();
    if (this.reader != null) {
      this.reader.readCompleted();
    }
    closed = true;
  }
Get scanners for compaction. We will create a separated reader for each store file to avoid
contention with normal read request.
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/StoreFileScanner.java