@Override
    public boolean nextRaw(List<? super ExtendedCell> outResults, ScannerContext context)
      throws IOException {
      boolean moreRows = super.nextRaw(outResults, context);
      HeartbeatHRegion.rowSleep();
      return moreRows;
    }
Custom ReversedRegionScanner that can be configured to sleep between retrievals of row Results
and/or column family cells
hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestScannerHeartbeatMessages.java