XIU2/CloudflareSpeedTest ? reverse-engineered prompt

Build me a small Go command line tool that helps me find the fastest Cloudflare IPs for my network.

I want it to test a list of IPv4 and IPv6 addresses, measure latency and download speed, then sort the results so the best IPs show up first. It should print a clean table in the terminal and also save everything to a CSV file so I can open it later. Please include simple flags for things like how many times to test each IP, how many IPs to download test after the latency check, how long each download test runs, and the port or URL to test against.

It would be great if it can work with Cloudflare IPs by default, but also let me use it for other CDN or website IP lists. If you need to look up current docs or best practices online, feel free to do that. Keep it easy to run on Windows, Linux, and Mac.