fn autoload(vm: &mut VM, self_val: Value, args: &Args2) -> VMResult {
    args.check_args_num(2)?;
    let const_name = vm[0].expect_string_or_symbol("1st arg")?;
    let mut arg1 = vm[1];
    let feature = arg1.expect_string("2nd")?.to_string();
    let mut parent = Module::new(self_val);
    parent.set_autoload(const_name, feature);
    Ok(Value::nil())
}
Module#autoload(const_name, feature) -> nil
https://docs.ruby-lang.org/ja/latest/method/Module/i/autoload.html
ruruby/src/builtin/module.rs