如何使用裁剪功能在konva组上添加拐角半径？

var stage = new Konva.Stage({
  container: 'container',
  width: 500,
  height: 300,
});

var layer = new Konva.Layer();
stage.add(layer);

var group = new Konva.Group();
layer.add(group);

var rect = new Konva.Rect({
  x: 50,
  y: 50,
  width: 200,
  height: 100,
  fill: 'blue',
});
group.add(rect);

var clipPath = new Konva.Path({
  data: 'M0,50 L0,150 Q0,200 50,200 L250,200 Q300,200 300,150 L300,50 Q300,0 250,0 L50,0 Q0,0 0,50 Z',
});
rect.clip(clipPath);

stage.draw();