set_cookie (Rack::Response)

    # File lib/rack/response.rb, line 56
        def set_cookie(key, value)
          case value
          when Hash
            domain  = "; domain="  + value[:domain]    if value[:domain]
            path    = "; path="    + value[:path]      if value[:path]
            # According to RFC 2109, we need dashes here.
            # N.B.: cgi.rb uses spaces...
            expires = "; expires=" + value[:expires].clone.gmtime.
              strftime("%a, %d-%b-%Y %H:%M:%S GMT")    if value[:expires]
            secure = "; secure"  if value[:secure]
            httponly = "; HttpOnly" if value[:httponly]
            value = value[:value]
          end
          value = [value]  unless Array === value
          cookie = Utils.escape(key) + "=" +
            value.map { |v| Utils.escape v }.join("&") +
            "#{domain}#{path}#{expires}#{secure}#{httponly}"

          case self["Set-Cookie"]
          when Array
            self["Set-Cookie"] << cookie
          when String
            self["Set-Cookie"] = [self["Set-Cookie"], cookie]
          when nil
            self["Set-Cookie"] = cookie
          end
        end