public void writeTo(T object, DataWriter writer) throws IOException {
        writeTo(object, 0, writer);
    }
@Test
    public void skipNull() throws Exception {
        StringWriter sw = new StringWriter();
        SomeNullProperty o = new SomeNullProperty();
        builder.get(SomeNullProperty.class).writeTo(o, TreePruner.DEFAULT, Flavor.JSON.createDataWriter(o, sw, config));
        assertEquals("{'_class':'SomeNullProperty','bbb':'bbb','ccc':null,'ddd':'ddd'}", sw.toString().replace('"','\''));
    }