gistfile1.txt

func downloadStream() -> AsyncThrowingStream<Double, Error> {
    AsyncThrowingStream { continuation in
        Task {
            var percentage = 0.0
            while percentage < 70 {
                try await Task.sleep(for: .milliseconds(10))
                let bits = Double.random(in: 0...0.3)
                percentage += bits
                continuation.yield(with: .success(percentage))
            }
            continuation.yield(with: .failure(.failedToDownload))
            continuation.finish()
        }
    }
}