使用`GroundPolylinePrimitive`创建贴地线，怎么动态改变其线宽

使用viewer.entities.add方式加载Entity类型的polyline

var blueLine = viewer.entities.add({
    name : 'Wide blue dashed line with a gap color',
    polyline : {
        positions : Cesium.Cartesian3.fromDegreesArrayHeights([-75, 40, 250000,
                                                        -125, 40, 250000]),
        width : 30,
        material : new Cesium.PolylineDashMaterialProperty({
            color : Cesium.Color.BLUE,
            gapColor: Cesium.Color.YELLOW
        }),
        clampToGround : true,
    }
});

可以直接设置其线宽：

blueLine.polyline.width=10;

如果改为使用GroundPolylinePrimitive创建贴地线，怎么动态改变其线宽

// Polyline Outline
scene.groundPrimitives.add(new Cesium.GroundPolylinePrimitive({
    geometryInstances : new Cesium.GeometryInstance({
        geometry : new Cesium.GroundPolylineGeometry({
            positions : Cesium.Cartesian3.fromDegreesArray([
                -122.2558, 46.1995,
                -122.1058, 46.1995
            ]),
            width : 10.0 //??怎么动态修改
        })
    }),
    appearance : new Cesium.PolylineMaterialAppearance({
        material : Cesium.Material.fromType(Cesium.Material.PolylineOutlineType)
    })
}));