need asynchronous network request demo

[BrentHuang]

I have a web application. When I click the login button on the page, it sends an HTTP post request to the server and then receive the response from the server. The whole process is required to be asynchronous.
While waiting for the server to respond, a loading animation is placed on the page.

Can you give me a demo of this scenario?

Finally, I will use flet build web to package and deploy this web application.

[BrentHuang]

When the web application starts, I create a session by session = aiohttp.ClientSession().

Then, in each page of the web application, I use this session object to communicate with the server.

When the web application exits, I want to call await session.close(). How can I do this?