The method 'EllipsoidalOccluder' seems to be missing, what should I use to replace it

CesiumJS
1 
    const occluder = new Cesium.EllipsoidalOccluder(
      this.viewer.scene.globe.ellipsoid,
      this.viewer.scene.camera.position
    );
    // Is it on the back of the Earth
    const res = occluder.isPointVisible(this.position);

The method ‘EllipsoidalOccluder’ seems to be missing, what should I use to replace it