BlobUploadProgress

The currently-landed segment set — the response of append and of the progress read
GET /api/blobs/uploads/{id} (the ingest precedent's BlocksResponse, in blob terms:
the caller's resume manifest and the source of the finalize echo).

{ "segments": [ { "segment_bytes": 0, "segment_hash": "string", "seq": 0 } ], "total_bytes": 0, "upload_id": "f2ef591b-135b-46fa-a604-3d4fda5bfbfb" }