@Override
    protected boolean doAction() throws Exception {
      ResultScanner rs = null;
      try {
        Scan s = new Scan();
        s.setBatch(2);
        s.addFamily(FAMILY);
        s.setFilter(new KeyOnlyFilter());
        s.readVersions(1);

        rs = table.getScanner(s);
        Result result = rs.next();
        return result != null && result.size() > 0;
      } finally {
        if (rs != null) {
          rs.close();
        }
      }
    }
Callable that will keep scanning for small amounts of data until the supplied future returns.
Returns the max time taken to scan.
hbase-it/src/test/java/org/apache/hadoop/hbase/mttr/IntegrationTestMTTR.java