@Override
          public void run() {
            try {
              region.flush(true);
              LOG.info("Finishing flush");
            } catch (IOException e) {
              LOG.info("Failed flush cache");
            }
          }
Count table.
@param hri        Region
@param flushIndex At what row we start the flush.
@param concurrent if the flush should be concurrent or sync.
@return Count of rows found.
hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestScanner.java