@Override
    public GeometryState createGroupedState()
    {
        return new GroupedGeometryState();
    }
@Test
    public void testCreateGroupedStateEmpty()
    {
        GeometryState state = factory.createGroupedState();
        assertNull(state.getGeometry());
        assertTrue(state.getEstimatedSize() > 0, format("Estimated memory size was %d", state.getEstimatedSize()));
    }