private static void addRows(int count, final MemStore mem) {
    long nanos = System.nanoTime();

    for (int i = 0; i < count; i++) {
      if (i % 1000 == 0) {

        System.out.println(i + " Took for 1k usec: " + (System.nanoTime() - nanos) / 1000);
        nanos = System.nanoTime();
      }
      long timestamp = System.currentTimeMillis();

      for (int ii = 0; ii < QUALIFIER_COUNT; ii++) {
        byte[] row = Bytes.toBytes(i);
        byte[] qf = makeQualifier(i, ii);
        mem.add(new KeyValue(row, FAMILY, qf, timestamp, qf), null);
      }
    }
  }
Adds {@link #ROW_COUNT} rows and {@link #QUALIFIER_COUNT}
@param hmc Instance to add rows to.
@return How many rows we added.
hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestDefaultMemStore.java