encode_fixed/encode_fixed.rs
use codex_percent::FixedEncoder;
fn main() {
let s = "💩";
let mut e = FixedEncoder::<12>::init();
let res = e.encode(s).unwrap();
assert_eq!(res, 12);
let t = core::str::from_utf8(e.cur_block().as_slice());
assert_eq!(t, Ok("%F0%9F%92%A9"));
println!("{} -> {}", s, t.unwrap());
}