Is your feature request related to a problem? Please describe.

#2681 introduces backend.VersionedReaderWriter to concurrently write to objects in object store.

While Azure supports the necessary precondition headers to perform versioned write and delete requests, the SDK we use doesn't cleanly expose these features and the current implementation is best-effort (similar to S3). Meaning, concurrent write/delete requests can still cause a data race if we are unlucky.

Describe the solution you'd like

Azure supports If-Match headers (similar to GCS) so we can do better! We should:

• investigate if we can use the current SDK (Azure/azure-storage-blob-go) to add If-Match headers on requests
• otherwise switch to the newer SDK (Azure/azure-sdk-for-go)

Describe alternatives you've considered

Additional context