Code sample #5 from https://medium.com/@johnsundell/type-erasure-using-closures-in-swift-1e6125231f8

Type-erasure-using-closures-in-Swift-4.swift

class AnyModelLoader<T>: ModelLoading {
    typealias CompletionHandler = (Result<T>) -> Void
    
    private let loadingClosure: (CompletionHandler) -> Void
    
    init<L: ModelLoading>(loader: L) where L.Model == T {
        loadingClosure = loader.load
    }
    
    func load(completionHandler: CompletionHandler) {
        loadingClosure(completionHandler)
    }
}