cesium 避免token过期或离线的方法

方法就是：自定义imageryProvider，将baseLayerPicker设置为false。就可以看到后台network将不会请求含有token的地址。

  var esri = new Cesium.ArcGisMapServerImageryProvider({
        url: 'https://services.arcgisonline.com/ArcGIS/rest/services/World_Imagery/MapServer',
        enablePickFeatures: false,
      })
      var viewer = new Cesium.Viewer('cesiumContainer', {
        imageryProvider: esri,
        selectionIndicator: false,
        animation: false,
        baseLayerPicker: false,
        geocoder: false,
        timeline: false,
        sceneModePicker: true,
        navigationHelpButton: false,
        infoBox: false,
        fullscreenButton: true,
      })