Based on the below information from "https://github.com/ring-clojure/ring/blob/master/SPEC", it appears that multiple Headers with the same name can be added. Although, I have not been able to get this to work. I did extend ArrayMap with a Map that allows duplicate name entries (which worked), but this breaks the definition of Map. Can you explain how I should format a "seq of Strings", to add multiple Set-Cookie Headers?

:headers
(Required, clojure.lang.IPersistentMap)
A Clojure map of HTTP header names to header values. These values may be
either Strings, in which case one name/value header will be sent in the
HTTP response, or a seq of Strings, in which case a name/value header will be
sent for each such String value.