Best approach for testing file downloads in Playwright?

I need to test that a CSV export button downloads the correct file with the right data. Our app generates the file server-side and streams it. I've tried `page.waitForEvent('download')` and it works sometimes, but I'm not sure how to: - Assert on the file contents (not just that a download happened) - Handle cases where the download URL is a redirect chain - Make this reliable in headless CI Any patterns or utility functions you'd recommend?