anchor.diff:  
     /// Remove document identified by [id] from specified [collection].
     Future<void> del(String collection, int id) =>
  -      _mc.invokeMethod('del', [_handle, collection, id]).catchError(_handleError);
  +      _mc.invokeMethod('del', [_handle, collection, id]).catchError(_errorHandler());
   
     /// Remove document identified by [id] from specified [collection].
     /// Doesn't raise error if document is not found.
  
positive.code:     if (_handle == null) {
        throw StateError('Closed');
      }
      return _mc.invokeMethod('close', [_handle]).catchError(_handleError);
    }
  
    /// Create instance of [query] specified for [collection].
  
negative.code: 
    static Future<EJDB2> _open(EJDB2Builder b) async {
      final hdl =
          await _mc.invokeMethod<int>('open', [null, b.path, b._asOpts()]).catchError(_errorHandler<int>());
      return EJDB2._(hdl);
    }
  
  