WWDC21-Concurrency-AsncSequence

1. for-await-in

for try await event in endpointURL.lines

• 可以中断循环：break/continue

• 可以和其他任务同步进行：

  • let iteration1 = async {
        for await quake in quakes { }
    }
    let iteration2 = async {
        do {
            for try await quake in quakeDownload { }
        } catch { }
    }
    <!--1-->
    

3. AsycnSequence APIs

• FileHandle.standardInput.bytes.lines

• URLSession.shared.bytes(from: url)

  • let (bytes, response) = try await URLSession.shared.bytes(from: url)
    guard let httpResponse = response as? HTTPURLResponse,
          httpResponse.statusCode == 200 /* OK */
    else {
        throw MyNetworkingError.invalidServerResponse
    }
    for try await byte in bytes {
        ...
    }
    <!--2-->

• Other Operations: map、max、prefix、...

4. BuildYourOwn - AsyncStream

let quakes = AsyncStream(Quake.self) { continuation in
    quakeHandlerFunc { quake in
        continuation.yield(quake)
    }
    continuation.onTermination = { _ in
        stopFunc()
    }
}