Code sample #8 from https://medium.com/@johnsundell/type-erasure-using-closures-in-swift-1e6125231f8

Type-erasure-using-closures-in-Swift-7.swift

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
   
    loadModel { result in
        switch result {
        case .success(let model):
            render(model)
        case .error(let error):
            render(error)
        }
    }
}