use rand::{SeedableRng, Rng};
let mut rng = rand_xorshift::XorShiftRng::from_seed(*b"The initial seed");
// creates a generator for sampling strings
let gen = rand_regex::Regex::compile(r"\d{4}-\d{2}-\d{2}", 100).unwrap();
// sample a few strings randomly
let samples = (&mut rng).sample_iter(&gen).take(3).collect::<Vec<String>>();
// all Unicode characters are included when sampling
assert_eq!(samples, vec![
    "꧰᪈৭᱃-𐒧᧒-௦۴".to_string(),
    "𞓰۳𑛐꩑-᪄９-໔᮹".to_string(),
    "𑛃𑃹९೭-١᥈-৫೪".to_string()
]);
// you could use `regex_syntax::Hir` to include more options
let mut parser = regex_syntax::ParserBuilder::new().unicode(false).build();
let hir = parser.parse(r"\d{4}-\d{2}-\d{2}").unwrap();
let gen = rand_regex::Regex::with_hir(hir, 100).unwrap();
let samples = (&mut rng).sample_iter(&gen).take(3).collect::<Vec<String>>();
assert_eq!(samples, vec![
    "2839-82-12".to_string(),
    "2857-86-63".to_string(),
    "0381-04-99".to_string(),
]);