anchor.diff:  
     static Future<EJDB2> _open(EJDB2Builder b) async {
       final hdl =
  -        await _mc.invokeMethod<int>('open', [null, b.path, b._asOpts()]).catchError(_handleError);
  +        await _mc.invokeMethod<int>('open', [null, b.path, b._asOpts()]).catchError(_errorHandler<int>());
       return EJDB2._(hdl);
     }
   
  
positive.code:     if (_handle == null) {
        throw StateError('Closed');
      }
      return _mc.invokeMethod('close', [_handle]).catchError(_handleError);
    }
  
    /// Create instance of [query] specified for [collection].
  
negative.code:         (json is! String) ? convert_lib.jsonEncode(json) : json as String,
          id
        ])
        .catchError(_errorHandler<int>())
        .then((v) => v as int));
  
    /// Apply rfc6902/rfc6901 JSON [patch] to the document identified by [id].
  