Why is OriginResponseBytes deprecated in logpull_options fields

Could you please elaborate more on the topic why is the OriginResponseBytes deprecated a documented here?

We need to compute analytics on the subdomains, but it prevent us to determine the amount of the traffic to the origin.
When will be the item deprecated?
Note that our clients download the partial requests so I am also interested in whether there is some segmentation of the request to the origin.
Kind regards
Bronislav Gabrhelik

Unfortunately this field was never populated in logs.

Instead, you can sum the ‚ÄúCacheResponseBytes‚ÄĚ field in Cloudflare Logs. To ensure you are only getting responses from your origin, make sure to filter out OriginResponseStatus equal to 0 or 304 (indicating a ‚Äúrevalidated‚ÄĚ response).