和MapRoute一样，如何在放大/缩小时缩放MapPolyline？

// 创建地图对象
var map = new qq.maps.Map(document.getElementById("map"), {
  center: new qq.maps.LatLng(39.916527, 116.397128),
  zoom: 10
});

// 创建MapPolyline对象
var polyline = new qq.maps.Polyline({
  path: [
    new qq.maps.LatLng(39.910, 116.370),
    new qq.maps.LatLng(39.920, 116.380),
    new qq.maps.LatLng(39.930, 116.390)
  ],
  strokeColor: "#FF0000",
  strokeWeight: 5,
  map: map
});

// 监听地图缩放事件
qq.maps.event.addListener(map, "zoom_changed", function() {
  // 获取当前缩放级别
  var zoom = map.getZoom();
  
  // 计算新的线段宽度
  var newWidth = 5 * zoom;
  
  // 更新MapPolyline的宽度
  polyline.setStrokeWeight(newWidth);
});