TelemetryInitializerBase is internal

Commit https://github.com/Microsoft/ApplicationInsights-aspnetcore/commit/b7db1a4940e715bd4081fdb4e1dde92592eff0f7 made the TelemetryInitializerBase internal. Was it really the intent? Isn't the purpose of this class to be reused to easily access the HttpContext from the request in a custom TelemetryInitilizer?

The other initializers are also internal, which would prevent from using them...