v1 of the element

Alternatively, we could build a map once, and use it afterwards. For example:
```
final _ALL_LEVELS = () {
  var map = {};
  Level.LEVELS.forEach((e) { map[e.name] = e; });
  return map;
}();

...
  void setLevelByName(String name) {
     var level = _ALL_LEVELS[name];
     if (level == null) {
         // warning
         return;
     }
     Logger.root.level = level;
  }
```