anchor.diff:      _mBlob = blob;
     }
   
  -  Future<hetima.WriteResult> write(Object o, int start, [int length=null]) {
  +  Future<hetima.WriteResult> write(Object o, int start, [int length = null]) {
       if (o is List<int> && !(o is type.Uint8List)) {
         o = new type.Uint8List.fromList(o);
       }
  
positive.code:         _writer = a;
          print("writer ${_writer} ${_writer.runtimeType}");
          _writer["onwrite"] = (d) {
          //  print("####[Z]");
            print("onwrite ${d}");
            _writer["abort"];
            ret.complete(new hetima.WriteResult());
          };
          
          _writer["onerror"] = (d) {
          //  print("####[Z]");
            print("onerror ${d}");
            _writer["abort"];
            ret.completeError({});
  
negative.code:     _file.callMethod("remove", [
        () {
          ret.complete({});
        },
        (b) {
          ret.completeError(b);
        }
      ]);
      return ret.future;
    }
  
    Future<hetima.WriteResult> truncate(int length) {
      Completer<hetima.WriteResult> ret = new Completer();
      _file.callMethod("createWriter", [
        (a) {
          js.JsObject _writer = a;
          try {
            _writer.callMethod("truncate", [length]);
          } catch (e) {
            ret.completeError(e);
          }
        },
        (b) {
          ret.completeError(b);
  