Task manager GET /status method returns two counters that reflect task progress -- total and completed. To make caller reason about their meaning, additionally there's progress_units field next to those counters.
This patch implements this progress report for backup task. The units are bytes, the total counter is total size of files that are being uploaded, and the completed counter is total amount of bytes successfully sent with PUT requests. To get the counters, the client::upload_file() is extended to calculate those.
fixes#20653Closesscylladb/scylladb#21144
* github.com:scylladb/scylladb:
backup_task: Report uploading progress
s3/client: Account upload progress for real
s3/client: Introduce upload_progress
s3: Extract client_fwd.hh
0ee0dd3ef4