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

[1] PostgreSQL: Proposal to provide the facility to set binary format
output for specific OID's per session
<https://www.postgresql.org/message-id/CADK3HHJxQ8ydLj98u7M0NGFh3x%3DrgoG9MVx8T6AanMbor2HTzw%40mail.gmail.com>
[2] PostgreSQL: default result formats setting
<https://www.postgresql.org/message-id/40cbb35d-774f-23ed-3079-03f938aacdae%402ndquadrant.com>
Dave Cramer