void readCompleted() {
    storeFileInfo.decreaseRefCount();
    if (context.getReaderType() == ReaderType.STREAM) {
      try {
        reader.close(false);
      } catch (IOException e) {
        LOG.warn("failed to close stream reader", e);
      }
    }
  }
Indicate that the scanner has finished reading with this reader. We need to decrement the ref
count, and also, if this is not the common pread reader, we should close it.
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/StoreFileReader.java