Relevant Issue: https://sagebionetworks.jira.com/browse/PLFM-4253

StorageLocationSettings are immutable and thus can be cached client side. The information in these will therefore not be repeated in the new implementations of UploadDestination and FileHandle.
The keyPath in ClientDelegatedS3UploadDestination is client generated: baseKey/<<UUID>>.
The key in ClientDelegatedS3FIleHandle, once uploaded will be baseKey/<<UUID>>/fileName.

Endpoint

Because the upload must occur client-side, the client must be responsible for creating the FIleHandle once uploading has completed