In https://developer.apple.com/videos/play/wwdc2018/405/ the demo app named Trailblazer shows in minute 28 something that looks like a customized UISegmentedControl to me for switching reviews/photos. The project view in that Xcode shot does not show 3rd party libs. I wonder how this control was made. I did not find source code for that app.
This is a screenshot of it: