What Internet connection speed do you need to watch iTunes's 4K movies? I'm looking for ballpark figures for what 4K movies from iTunes use in terms of network bandwidth.

Is this documented or something that's a known range?
Apple recommends a minimum speed of 25 Mbps for 4K streaming


Find and watch movies with 4K, HDR, or Dolby Vision - Apple Support

A nice tool to estimate what bandwidth is needed for various video formats is the Black Magic Disk Speed Test app: https://itunes.apple.com/us/app/blackmagic-disk-speed-test/id425264550?mt=12