Can we use the sub instead of identity id for private/protected storage?

** Which Category is your question related to? **
Amplify Storage

** What AWS Services are you utilizing? **
S3, Cognito

** Provide additional details e.g. code snippets **
Right now when saving a private or protected object in S3 using Amplify, we get the user identity id in the folder name, instead of identity id. When you want to access other users' objects, you need to know their identity id. In the post confirmation trigger in Cognito, we get the user sub only. We get the identity id when the user logs in.

I am currently resorting to updating the identity id in my dynamodb on log in every time. Is there a reason you are using the identity id instead of sub? I think sub would streamline it even better.