public static IntRef ofInt(int value) {
        return new IntRef(value);
    }
@Test
    public void testIntRef() {
        PrimitiveRef.IntRef ref = PrimitiveRef.ofInt(3);
        assertEquals(3, ref.value++);
        assertEquals(4, ref.value);
        assertEquals(5, ++ref.value);
        assertEquals(5, ref.value);
    }