anchor.diff:   * A loose git object.
    */
   class LooseObject {
  -  int _size;
  -  String _type;
  +  int size;
  +  int type;
  +
  +  static Map<String, int> _typeMap = {
  +    ObjectTypes.COMMIT : 1,
  +    ObjectTypes.TREE : 2,
  +    ObjectTypes.BLOB : 3
  +  };
   
     // Represents either an ArrayBuffer or a string representation of byte
     //stream.
  
positive.code: class TreeObject extends GitObject {
  
    List<TreeEntry> entries;
  
    TreeObject( [String sha, Uint8List data]) : super(sha, data) {
      this._type = ObjectTypes.TREE;
      _parse();
    }
  
  
negative.code:       this.data = buf.substring(i + 1, buf.length);
      }
      List<String> parts = header.split(' ');
      this.type = _typeMap[parts[0]];
      this.size = int.parse(parts[1]);
    }
  }
  