public int add(Object o) {
        HollowTypeMapper typeMapper = getTypeMapper(o.getClass(), null, null);
        return typeMapper.write(o);
    }
@Test
    public void testIntPreassignedOrdinal() {
        HollowObjectMapper mapper = new HollowObjectMapper(writeStateEngine);
        TypeWithIntAssignedOrdinal o = new TypeWithIntAssignedOrdinal();
        o.__assigned_ordinal = 1;
        mapper.add(o);
        // int fields are ignored
        Assert.assertEquals(1, o.__assigned_ordinal);
    }