anchor.diff:      if (shouldLog(level)) {
         _streamController.add({
           'level':level,
  +        'fullSource': fullSource,
           'source':source,
           'event':event,
           'meta':getMetaData != null ? getMetaData() : null,
  
positive.code: 
  class Logger {
  
    final source;
    Level logLevel = null;
    Logger _parent;
  
negative.code:       parent = new Logger(source.substring(0, dot));
        thisName = source.substring(dot + 1);
      }
      return new Logger._internal(source, thisName, parent);
    }
  
    Logger._internal(this.fullSource, this.source, this._parent);
  
  }
  