Error removing CZML datasource when start and end time in clock interval are the same

[fc]

It seems to only throw an error when using the result from the promise.

Code:

var viewer = new Cesium.Viewer("cesiumContainer");
async function doIt() {
  var czml = [
    {
      "id":"document",
      "version":"1.0",
      "clock":
        {
          "interval":"2020-01-01T00:00:00+00:00/2020-01-01T00:00:00+00:00",
          "currentTime":"2020-01-01T00:00:00+00:00",
          "multiplier":30,
          "range":"CLAMPED",
          "step":"SYSTEM_CLOCK_MULTIPLIER"
        }
    }
  ];
  var dataSourcePromise = Cesium.CzmlDataSource.load(czml);
  viewer.dataSources.add(dataSourcePromise);
  const dataSource = await dataSourcePromise;
  viewer.dataSources.remove(dataSource);
}


doIt();

Error:

Uncaught (in promise) TypeError: this._dataSourceChangedListeners[id] is not a function
    at Viewer._onDataSourceRemoved (VM332 Cesium.js:304106)
    at Event.raiseEvent (VM332 Cesium.js:14039)
    at DataSourceCollection.remove (VM332 Cesium.js:195798)
    at doIt (<anonymous>:24:22)

Sandcastle example:
https://sandcastle.cesium.com/#c=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

Browser:
Chrome

Operating System:
macOs

Workaround / prevention:
Don't allow clock interval have the same start/end time.

[OmarShehata]

@fc this Sandcastle doesn't throw an error for me. Are you seeing different behavior?

[mramato]

@fc change doIt(); to doIt().catch(e => console.log(e)); and you'll see the error.

Looks like a clear cut bug to me (should hopefully be an easy fix as well)

[fc]

On the sandcastle, the exception displays in the browser console without needing to log it.