@Override
    public long getCost() {
        return super.getCost() + REFERENCE_COST_IN_BYTES
                + (value == null ? 0L : value.getHeapCost());
    }
@Test
    public void testGetCosts() {
        assertTrue(record.getCost() > 0);
        assertTrue(recordSameAttributes.getCost() > 0);
        assertTrue(recordOtherKeyAndValue.getCost() > 0);
    }