Dyanmo streams exposing sharding might help develop a better Dynamo Backfill

[mpawliszyn]

Maybe by leveraging Kinesis we can assume better long term sharding support:
https://aws.amazon.com/blogs/database/dynamodb-streams-use-cases-and-design-patterns/

https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Streams.html