update method
Forwards a message to the underlying ViewportModel.
Implementation
(ViewportModel, Cmd?) update(Msg msg) {
final Stopwatch? sw = TuiTrace.enabled ? Stopwatch() : null;
sw?.start();
final (vp, cmd) = _model.update(msg);
_model = vp;
if (sw != null) {
sw.stop();
TuiTrace.log(
'viewport.controller.update ${msg.runtimeType} '
'y=${_model.yOffset} ${sw.elapsedMicroseconds}us',
);
}
return (vp, cmd);
}