Checkpoint support with blob storage

[nageshs28]

Description

Understand default checkpoint store with Kafka API. Where it is stored since we don't provide any external store?
https://learn.microsoft.com/en-us/java/api/overview/azure/messaging-eventhubs-checkpointstore-blob-readme?view=azure-java-stable

How to reproduce

Has it worked previously?

Checklist

https://learn.microsoft.com/en-us/java/api/overview/azure/messaging-eventhubs-checkpointstore-blob-readme?view=azure-java-stable

IMPORTANT: We will close issues where the checklist has not been completed or where adequate information has not been provided.

Please provide the relevant information for the following items:

• SDK (include version info): <REPLACE with e.g., kafka-python/Java SDK/confluent-kafka-dotnet with version info>
• Sample you're having trouble with: <REPLACE with e.g., Java quickstart>
• If using Apache Kafka Java clients or a framework that uses Apache Kafka Java clients, version: <REPLACE with e.g., 1.1.0>
• Kafka client configuration: <REPLACE with e.g., auto.reset.offset=earliest, ..> (do not include your connection string or SAS Key)
• Namespace and EventHub/topic name
• Consumer or producer failure <REPLACE with e.g., Consumer failure>
• Timestamps in UTC <REPLACE with e.g., Nov 7 2018 - 17:15:01 UTC>
• group.id or client.id <REPLACE with e.g., group.id=cg-name>
• Logs provided (with debug-level logging enabled if possible, e.g. log4j.rootLogger=DEBUG) or exception call stack
• Standalone repro <REPLACE with e.g., Willing/able to send scenario to repro issue>
• Operating system: <REPLACE with e.g., Ubuntu 16.04.5 (x64) LTS>
• Critical issue

If this is a question on basic functionality, please verify the following:

• Port 9093 should not be blocked by firewall ("broker cannot be found" errors)
• Pinging FQDN should return cluster DNS resolution (e.g. $ ping namespace.servicebus.windows.net returns ~ ns-eh2-prod-am3-516.cloudapp.net [13.69.64.0])
• Namespace should be either Standard or Dedicated tier, not Basic (TopicAuthorization errors)