What problem does this feature solve?

Rollup supports this, but Rolldown does not.
This forces me to export an array of build configs instead of one config.
The multiple builds are not as fast as only 1 build of course.

Here's how it looks:

• with rollup https://github.com/adazzle/react-data-grid/blob/7f9fd89ea34ada050834238d78c9e73828b62af4/rollup.config.js#L13-L26
• with rolldown https://github.com/adazzle/react-data-grid/blob/670ba11cfc2faedf274e3aa21f2f8c818e7bdd0a/rolldown.config.js#L13-L33

What does the proposed API look like?

export default defineConfig({
  output: [
    {
      // output options
    },
    {
      // output options
    }
  ],

I simply want feature parity with Rollup in that regard.