how to add polyline overlay on Cesium3DTileset

1. A concise explanation of the problem you're experiencing.

i want to add custom polyline or polygon with outline on Cesium ,before do this i have added a Cesium3DTileset on Cesium,i want to all entites which i added overlay the 3dTileSet

2. A minimal code example. If you've found a bug, this helps us reproduce and repair it.

viewer.entities.add({
             polygon : { // it works and i expect
               hierarchy :e.polygon.hierarchy,
               material : Cesium.Color.RED.withAlpha(0.5),
               classificationType : Cesium.ClassificationType.BOTH
             }
           });

viewer.entities.add({
             polygon : { // i want to show polygon border, it not works
               hierarchy :e.polygon.hierarchy,
               material : Cesium.Color.RED.withAlpha(0.5),
               classificationType : Cesium.ClassificationType.BOTH,
               outline:true
             }
           });

PolylineGraphics do not have classificationType property,so i have no idea for this case.

3. Context. Why do you need to do this? We might know a better way to accomplish your goal.

i want to add wms overlay Cesium3DTileset,but there is no way,so i use js to load wms data and render with js, i hope all renderable layers,entites overlay Cesium3DTileset

4. The Cesium version you're using, your operating system and browser.
Cesium 1.45.0 chrome

It is not possible yet to drape polylines over 3D Tiles.

But… we have a PR open for polylines on terrain and 3D Tiles support should be soon to follow.