@Override
    public StringBuffer format(Object obj, StringBuffer result, FieldPosition pos) {
        return format.format(toArgs((Attributes) obj), result, pos);
    }
@Test
    public void testOffset() {
        Attributes attrs = new Attributes();
        attrs.setString(Tag.SeriesNumber, VR.IS, "1");
        attrs.setString(Tag.InstanceNumber, VR.IS, "2");
        assertEquals("101/1", new AttributesFormat(TEST_PATTERN_OFFSET).format(attrs));
    }