[FEATURE REQUEST]: Support Spark .Net when use AAD Auth

[xinyeah]

Feature Requests:

• What issue are you trying to solve?
  We want to use Service Principle and Certificate to connect EHs on Spark .Net. The below document support AAD auth for Scala Spark: https://github.com/Azure/azure-event-hubs-spark/blob/master/docs/use-aad-authentication-to-connect-eventhubs.md
  But the sample code doesn't work for Spark .Net because we cannot pass down the call back class in the parameter options.

• How do you want to solve it?

• What is your use case for this feature?
  We want to use Service Principle and Certificate to connect EHs on Spark .Net.