StoringContinuations.swift

class DelegateWrapper: NSObject, ObservableObject, CLLocationManagerDelegate {
    private var continuation: CheckedContinuation<Data?, Error>?
    private let dataService = SomeClassThatReturnsData()

    override init() {
        super.init()
        dataService.delegate = self
    }

    func requestData() async throws -> Data? {
        try await withCheckedThrowingContinuation { continuation in
            continuation = continuation
            dataService.requestData()
        }
    }

    func receivedData(_ data: Data) {
        continuation?.resume(returning: data)
    }

    func receivedError(_ error: Error) {
        continuation?.resume(throwing: error)
    }
}

struct ContentView: View {
    @StateObject private var delegateWrapper = DelegateWrapper()

    var body: some View {
        Button("Load Data") {
            Task {
                if let data = try? await delegateWrapper.requestData() {
                    print("data: \(data)")
                } else {
                    print("no data.")
                }
            }
        }
    }
}