iOS crash when close scanPage

[butterflyXX]

• (FlutterError * _Nullable)onCancelWithArguments:(id _Nullable)arguments {
  _eventSink = nil;
  [_eventChannel setStreamHandler:nil];
  return nil;
  }

[_eventChannel setStreamHandler:nil]; Thread 1: EXC_BAD_ACCESS (code=2, address=0x51932b7b90)

[rhymelph]

need more information