null value separator reading doesn't work properly

[Marekkon5]

Hello, if I use a null (\0) separator for my values, then save and load again, the read frame only has the first value.
Example / test:

#[test]
fn test_null() {
    let mut tag = Tag::new();
    tag.add_frame(Frame::text("TPE1", "artist 1\0artist 2\0artist 3"));
    let mut buf = vec![];
    tag.write_to(std::io::Cursor::new(&mut buf), Version::Id3v23).unwrap();
    let tag = Tag::read_from(&buf[..]).unwrap();
    assert_eq!(tag.text_for_frame_id("TPE1").unwrap(), "artist 1\0artist 2\0artist 3");
}

Result:

left: `"artist 1"`,
right: `"artist 1\u{0}artist 2\u{0}artist 3"`'

Thanks