title: How to store a message from the client in the server and send it further via some route in Flask
body: <p>From a web application, this is making a request to the backend application (Python with Flask and flask-socketio). From this route on the backend, an emit should be done to a socketio client standalone application. This works fine, but when the client app sends back a message directly after, I want to retrieve this message and send it back in my route to the web application. The message I get back from the client via a callback will be asynchronous, so how in the simplest manner could this be achieved? Each time I fetch the message from the client, the route has already sent back a reply to the web app without the message.</p>
  <p>I fully understand that this flow is usually not normal, but can this be achieved without saving this message into a database, but store it somewhere on the backend and send it back to the web app?</p>