Adaptive Sampling Default SetLastObservedSamplingPercentage

[czb182]

Why is SetLastObservedSamplingPercentage only called for Request type telemetry by default?

I'm customized adaptive sampling, so I have disabled in config and setting up in code per this documentation
https://learn.microsoft.com/en-us/azure/azure-monitor/app/sampling-classic-api#configure-sampling-settings

I was taking the default setup from this repo to build upon it.

Notice that the default adaptive sampling uses a sampling callback to setup lastobserved for request telemetry

ApplicationInsights-dotnet/NETCORE/src/Shared/Implementation/TelemetryConfigurationOptionsSetup.cs

Line 332 in e34286b

configuration.SetLastObservedSamplingPercentage(SamplingTelemetryItemTypes.Request, newPercentage);

this is not shown in documentation, and I gather its to increase accuracy of sampling, but why not set last observed for all types included in sampling?

Not sure if this is issue or not. Or maybe because sampling seems to be done at the operation level (seemingly) you only need to set for one type?