public long getExpectedNumberOfKeys() {
      return expectedNumberOfKeys.get();
    }
Custom LoadTestDataGenerator. Uses key generation and verification from LoadTestKVGenerator.
Creates 3 column families; one with an integer column to filter on, the 2nd one with an integer
column that matches the first integer column (for test-specific verification), and byte[] value
that is used for general verification; and the third one with just the value.
hbase-it/src/test/java/org/apache/hadoop/hbase/IntegrationTestLazyCfLoading.java