anchor.diff:     * Effective level considering the levels established in this logger's parents
      * (when [hierarchicalLoggingEnabled] is true).
      */
  -  Level get level() {
  +  Level get level {
       if (hierarchicalLoggingEnabled) {
         if (_level != null) return _level;
         if (parent != null) return parent.level;
  
positive.code:    * instance:
     *    logger.on.record.add((record) { ... });
     */
    LoggerEvents get on() => new LoggerEvents(this);
  
    /** Adds a handler to listen whenever a log record is added to this logger. */
    void _addHandler(LoggerHandler handler) {
  
negative.code:   final String name;
  
    /** The full name of this logger, which includes the parent's full name. */
    String get fullName =>
        (parent == null || parent.name == '') ? name : '${parent.fullName}.$name';
  
    /** Parent of this logger in the hierarchy of loggers. */
  