@Override
    public ColumnStatistics buildColumnStatistics()
    {
        if (hasEntries && collectKeyStats) {
            MapStatistics mapStatistics = new MapStatistics(entries.build());
            return new MapColumnStatistics(nonNullValueCount, null, rawSize, storageSize, mapStatistics);
        }
        return new ColumnStatistics(nonNullValueCount, null, rawSize, storageSize);
    }
@Test
    public void testAddEmptyMapStatistics()
    {
        MapColumnStatisticsBuilder builder = new MapColumnStatisticsBuilder(true);
        ColumnStatistics columnStatistics = builder.buildColumnStatistics();
        assertEquals(columnStatistics.getClass(), ColumnStatistics.class);
        assertEquals(columnStatistics.getNumberOfValues(), 0);
        assertNull(columnStatistics.getMapStatistics());
    }