anchor.diff:  
       log.debug('readSopInstance: fmi = $fmi');
       int start = readIndex;
  -    var aMap = readDataset();
  +    var deMap = readDataset();
       int lengthInBytes = readIndex - start;
  -    Dataset ds = new Dataset(aMap, false, lengthInBytes);
  +    Dataset ds = new Dataset.root(deMap, lengthInBytes: lengthInBytes);
   
       Instance instance = ActivePatients.addSopDataset(path, lengthInBytes, fmi, ds);
   
  
positive.code:   /// This is the top-level entry point for reading a [Dataset].
    Map<int, Attribute> readDataset() {
      final Logger log = new Logger("readDataset");
      Map<int, Attribute> aMap = {};
      while (isReadable) {
        Attribute a = readAttribute();
        aMap[a.tag] = a;
        if (a.tag == kPixelData) {
          //print('PixelData(${tagToDcm(a.tag)}): ${a.vr}, length= ${a.length}');
          log.debug('PixelData(${tagToDcm(a.tag)}): ${a.vr}, length= ${a.length}');
  
negative.code:       }
      }
      log.debug('DcmBuf: $this');
      return deMap;
    }
  
    //TODO: move to a utilities file for TypedData
  