Performance Issues on updating the color of the polylines

CesiumJS
1

Hi,
I encountered a performance issue when updating the colors of the polyline entities periodically. It basically "freeze" for a few seconds during the updates. Below is my sample app (Sandcastle, version 1.54), and how can it be improve further?

var viewer = new Cesium.Viewer('cesiumContainer');
var lon;
var lat;
var count = 4000;
for (var i = 0 ; i < count; ++i) {
    lon = Cesium.Math.randomBetween(103,104);
    lat = Cesium.Math.randomBetween(1,2);
    viewer.entities.add({
    polyline : {
        positions: Cesium.Cartesian3.fromDegreesArray([lon, lat, lon+0.05, lat+0.05]),
        width : 5,
        material : Cesium.Color.fromRandom(),
        clampToGround : true
    }
});
}

viewer.zoomTo(viewer.entities);

multiStep();

function multiStep() {
    var i;
    var newtime = 10000;
    viewer.entities.suspendEvents();
    for (i=0; i<viewer.entities.values.length;i++) {
        viewer.entities.values[i].polyline.material.color.setValue(Cesium.Color.fromRandom());
    }
    viewer.entities.resumeEvents();
  if (true) {
    setTimeout(multiStep, newtime);
  }
}