PatchUpdateVerbatimCheckpoint

Uploads a checkpoint for a service-managed update as a verbatim byte array, bypassing JSON marshalling. Unlike PatchUpdateCheckpoint which accepts a structured deployment object and re-serializes it (which may compact data), this endpoint preserves the exact bytes provided by the client and uploads them directly to blob storage. This maintains byte-level fidelity of the checkpoint data. Returns 403 for preview operations. Returns 409 if the update has not started, has been cancelled, timed out, or already completed. Requires update token authentication.