Zeroconf Networking Browser for iOS
Use Xcode. If it does not "just work", file an issue.
Automated tests are currently non-existant. A small test helper is at https://github.com/rhwood/hola-server, however, until the Swift Package Manager is supported for iOS programming and testing, that's not really usable (I am not about to introduce CocoaPods or Carthage as a dependency on this project).