@Override
    public void serialize(Asn1OutputStream out, byte[] obj) {
        out.write(0);
        out.write(obj);
    }
@Test
    public void shouldSerialize() {
        assertArrayEquals(
            new byte[] { 0, 1, 2, 3 },
            serialize(new BitStringToByteArrayConverter(), byte[].class, new byte[] { 1, 2, 3 })
        );
    }