What problem does this feature solve?

https://rspack.dev/zh/plugins/webpack/internal-plugins#progressplugin

The documentation mentions it, but the function does not take effect when passed in!
There is an option to enable progress in webpack-dev-server:

https://github.com/webpack/webpack-dev-server/blob/530db07435fd5c826aa105b2825324e10f2aea18/lib/Server.js#L1686

What does the proposed API of configuration look like?

Refer to the functional API of webpack.

https://github.com/webpack/webpack-dev-server/blob/530db07435fd5c826aa105b2825324e10f2aea18/lib/Server.js#L1686