parse static method

Implementation

static GooglePlusUserNameUrl? parse(String url) {
  var matches =
      RegExp(r'(?:https?:)?\/\/plus\.google\.com\/\+(?<username>[A-z0-9+]+)')
          .allMatches(url);
  var username = matches.getValue("username");
  if (username == null) return null;
  return GooglePlusUserNameUrl._(username);
}