Explanation

Scenario: You have a shared library named PolicyLib that contains functionality common to all ASP.NET Core web services and applications. The PolicyLib library must:
Exclude non-user actions from Application Insights telemetry.
Provide methods that allow a web service to scale itself.
Ensure that scaling actions do not disrupt application usage.
Box 1: ITelemetryInitializer
Use telemetry initializers to define global properties that are sent with all telemetry; and to override selected behavior of the standard telemetry modules.
Box 2: Initialize
Box 3: Telemetry.Context
Box 4: ((EventTelemetry)telemetry).Properties["EventID"]
Reference:
https://docs.microsoft.com/en-us/azure/azure-monitor/app/api-filtering-sampling