// SearchRepositoriesRequest conforms to Request protocol.
let request = SearchRepositoriesRequest(query: "swift")

// Session receives an instance of a type that conforms to Request.
Session.send(request) { result in
    switch result {
    case .success(let response):
        // Type of `response` is `[Repository]`,
        // which is inferred from `SearchRepositoriesRequest`.
        print(response)

    case .failure(let error):
        self.printError(error)
    }
}