Can I get native (X11) window handles?

I was trying to port a little tool I made with Qt 5.2 to go/qml, but in this tool, I need access to the native X11 handle through the `winId()` QWindow method for sending a X11 message for setting "always on top" flag for the window (this is just a brightness control tool, so this is applicable). It seems there's no `qml.Window` method/member that gives me this native handle so I can use it with [`BurntSushi/xgb`](https://github.com/BurntSushi/xgb)? It would be nice to have access for that.