Add VB sample to AuthenticatedStream class

[mairaw]

This is the topic: https://docs.microsoft.com/en-us/dotnet/api/system.net.security.authenticatedstream?view=netframework-4.7.2

[obelink]

I will do this class, methods & properties.

[obelink]

Hi Maira.. can you assign this task on my name?

[mairaw]

Done @obelink

[mairaw]

@rpetrusha finished this task with #2448. Closing.