module Rack::Utils

# => "myname=; max-age=0; expires=Thu, 01 Jan 1970 00:00:00 GMT"
delete_set_cookie_header("myname")

to *remove* any matching cookie.
+value+. When used with the +set-cookie+ header, it will cause the client
a +max_age+ of 0 seconds, an +expires+ date in the past and an empty
attributes as outlined by set_cookie_header. The encoded cookie will have
deleted. The +value+ may be an instance of +Hash+ and can include
set_cookie_header for the purpose of causing the specified cookie to be
Generate an encoded string based on the given +key+ and +value+ using

delete_set_cookie_header(key, value = {}) -> encoded string
:call-seq:

def delete_set_cookie_header(key, value = {})
  set_cookie_header(key, value.merge(max_age: '0', expires: Time.at(0), value: ''))
end