pub fn subscribe_to_window_events(&self, window: xproto::Window) -> Result<()> {
        let mask = xproto::EventMask::ENTER_WINDOW
            | xproto::EventMask::FOCUS_CHANGE
            | xproto::EventMask::PROPERTY_CHANGE;
        self.subscribe_to_event(window, mask)
    }
Subscribe to the wanted events of a window.
display-servers/x11rb-display-server/src/xwrap/window.rs