Implement rectangle rotation

class Square extends PositionComponent {

  var rotationSpeed = 0.3;

  var velocity = Vector2(0, 0).normalized() * 25;

  var squareSize = 128.0;

  var color = BasicPalette.white.paint()
    ..style = PaintingStyle.stroke
    ..strokeWidth = 2;


 @override
  Future<void> onLoad() async {
    super.onLoad();
    size.setValues(squareSize, squareSize);
    anchor = Anchor.topRight;
  }

  @override
  //
  // update the inner state of the shape
  // in our case the position based on velocity
  void update(double dt) {
    super.update(dt);
    // speed is refresh frequency independent
       position += velocity * dt;
    var angleDelta = dt * rotationSpeed;
    angle = (angle + angleDelta) % (2 * pi);
  }

  @override
  //
  // render the shape
  void render(Canvas canvas) {
    super.render(canvas);
    canvas.drawRect(size.toRect(), color);
  }
}

angle = (angle + angleDelta) % (2 * pi);