Request for comment on setting binary format output per session

Greetings,

In [1] I proposed a patch that used a GUC to request a list of OID's to be returned in binary format. 

In [2] Peter Eisentraut proposed a very similar solution to the problem.

In [2] there was some discussion regarding whether this should be set via GUC or a new protocol message. 

I'd like to open up this discussion again so that we can move forward. I prefer the GUC as it is relatively simple and as Peter mentioned it works, but I'm not married to the idea. 

Regards,

Dave