OPDS 1 feeds compress really well; about 6:1. The less time an app server spends sending OPDS over the wire, the sooner that app server can move on to servicing the next request.

I made a @compressible decorator for controllers in the library registry, to implement https://jira.nypl.org/browse/SIMPLY-1778. I can copy it over to core and do the same thing in the circulation manager.