@Override
          public void run() {
            byte[] row = Bytes.toBytes("row" + count);
            Put put = new Put(row);
            put.setDurability(Durability.SYNC_WAL);
            byte[] value = Bytes.toBytes(String.valueOf(count));
            for (byte[] family : families) {
              for (byte[] qualifier : qualifiers) {
                put.addColumn(family, qualifier, count, value);
              }
            }
            try {
              region.put(put);
            } catch (IOException e) {
              throw new RuntimeException(e);
            }
          }
HBASE-16429 Make sure no stuck if roll writer when ring buffer is filled with appends
@throws IOException if IO error occurred during test
hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestHRegion.java