code: func SendRootEvent(xu *xgbutil.XUtil, ev xgb.Event, evMask uint32) error {
  	return xproto.SendEventChecked(xu.Conn(), false, xu.RootWin(), evMask,
  		string(ev.Bytes())).Check()
  }
docs: // SendRootEvent takes a type implementing the xgb.Event interface, converts it
  // to raw X bytes, and sends it to the root window using the SendEvent request.