* Let `T` denote `typename range_value<decltype(rng)>::type`, then `regex` has the type `basic_regex<T>` or is implicitly convertible to one of these types.
* `i` has the type `int`.
* the `value_type` of `rndRng` is `int`.
* `flags` has the type `regex_constants::syntax_option_type`.
* [*Returns:] A range whose iterators behave as if they were the original iterators wrapped in `regex_token_iterator`. The first iterator in the range would be constructed by forwarding all the arguments of `tokenized()` to the `regex_token_iterator` constructor.
* [*Throws:] Whatever constructing and copying equivalent `regex_token_iterator`s might throw.