is_object method Null safety

Implementation

bool is_object() {
  final constructor =
      _dll_handle.lookupFunction<_Context_isObject_c, _Context_isObject_dart>(_context_namespace + 'isObject');
  final exception = _getException();

  bool res = constructor(this._impl, exception);

  tdvCheckException(exception, _dll_handle);

  return res;
}