@Override
    public int size() {
        if (entries == null) {
            return 0;
        }
        return entries.size();
    }
@Test
    public void testSize_whenEmpty() {
        List<Map.Entry> emptyList = Collections.emptyList();
        ResultSet resultSet = new ResultSet(emptyList, IterationType.KEY);
        assertEquals(0, resultSet.size());
    }