instance method unpacked_cookie_data

# File actionpack/lib/action_controller/session/cookie_store.rb, line 154
        def unpacked_cookie_data(env)
          env["action_dispatch.request.unsigned_session_cookie"] ||= begin
            stale_session_check! do
              request = Rack::Request.new(env)
              session_data = request.cookies[@key]
              unmarshal(session_data) || {}
            end
          end
        end