traffic method
Returns a dictionary of the Subreddit's traffic statistics.
Raises an error when the traffic statistics aren't available to the authenticated user (i.e., not a moderator of the subreddit).
Implementation
Future<Map> traffic() async => (await _throwOnInvalidSubreddit(() async =>
await reddit.get(apiPath['about_traffic']
.replaceAll(SubredditRef._subredditRegExp, _name))) as Map?)!;