CZML animation play speed

[imakihi]

Hi there.
I wanted to control time series animation play speed with a clock setting but it doesn't work. I looked a the Cesium Sandcastle and tested various settings. It worked with the example.
https://sandcastle.cesium.com/index.html?src=CZML%20Polygon%20-%20Intervals%2C%20Availability.html&label=CZML

However, I set a clock like followings but those settings didn't change anything....

"clock": {"interval": "2021-02-20T12:00:00+09:00/2021-02-20T23:00:00+09:00", "currentTime": "2021-02-04T12:00:00+09:00", "multiplier": 100}

"clock": {"interval": "2021-02-20T12:00:00+09:00/2021-02-20T23:00:00+09:00", "currentTime": "2021-02-04T12:00:00+09:00", "multiplier": 1}

"clock": {"interval": "2021-02-20T12:00:00+09:00/2021-02-20T23:00:00+09:00", "currentTime": "2021-02-04T12:00:00+09:00", "multiplier": 0.1}

This is my CZML for this test.

[ { "id": "document", "name": "CZML Geometries: polyline", "version": "1.0", "clock": {"interval": "2021-02-20T12:00:00+09:00/2021-02-20T23:00:00+09:00", "currentTime": "2021-02-04T12:00:00+09:00", "multiplier": 100} }, { "id": "tokyo station left", "name": "red polyline", "availability": "2021-02-20T12:00:00-09:00/2021-02-20T23:00:00-09:00", "polyline": { "positions": { "cartographicDegrees": [139.76585490589437,35.68141787511337,5,139.76570854372,35.68145053444155,5,139.7656819324155,35.68142513274185,5,139.76565169229684,35.68131626831459,5] }, "material": { "polylineArrow": { "color": { "rgba": [255, 0, 0, 200] } } }, "width": {"number":[ "2021-02-20T12:00:00-09:00",4, "2021-02-20T18:00:00-09:00",200, "2021-02-20T23:00:00-09:00",10 ]} } } ]

Can anybody help me to understand why my settings didn't work.

Thank you!

Hiroo