This file WorkersRealTimeStatisticsResource.cs has an incomplete model definition:

[JsonProperty("activity_statistics")]
public List<object> ActivityStatistics { get; private set; }

The ActivityStatistics are defined as a list of objects. This causes the system.text.json deserializer to skip and always return empty Activity Statistics.

This is an issue with Azure Functions under Net6 which wants to use system.text.json as the default instead of Newtonsoft JsonCovert.

Could you define the actual statistics model instead of listing as "object"?

This issue also effects:

WorkersCumulativeStatisticsResource.cs:

[JsonProperty("activity_durations")]
public List<object> ActivityDurations { get; private set; }

WorkerStatisticsResource.cs

[JsonProperty("cumulative")]
public List<object> Cumulative { get; private set; }

On a related note, you have a number of tests that test these resources but the test should not pass as the result is returning empty instead of the correct values.