delete_cookie (Rack::Response)

    # File lib/rack/response.rb, line 81
        def delete_cookie(key, value={})
          unless Array === self["Set-Cookie"]
            self["Set-Cookie"] = [self["Set-Cookie"]].compact
          end

          self["Set-Cookie"].reject! { |cookie|
            cookie =~ /\A#{Utils.escape(key)}=/
          }

          set_cookie(key,
                     {:value => '', :path => nil, :domain => nil,
                       :expires => Time.at(0) }.merge(value))
        end