swift - 由于 swift 中的参数类型，无法在闭包下执行

Question

我有一种将内容上传到 S3 Bucket AWS 的情况。

我正在使用下面的代码并且代码没有被编译。

请指教。

let data = // The data to upload

let expression = AWSS3TransferUtilityUploadExpression()
expression.progressBlock = {(task, progress) in DispatchQueue.main.async(execute: {
        // Do something e.g. Update a progress bar.
    })
}

let completionHandler = { (task, error) -> Void in
    DispatchQueue.main.async(execute: {
        // Do something e.g. Alert a user for transfer completion.
        // On failed uploads, `error` contains the error object.
    })
}

let  transferUtility = AWSS3TransferUtility.default()

transferUtility.uploadData(data,
            bucket: S3BucketName,
            key: S3UploadKeyName,
            contentType: "image/png",
            expression: expression,
            completionHandler: completionHandler).continueWith { (task) -> AnyObject! in
    if let error = task.error {
        print("Error: \(error.localizedDescription)")
    }

    if let _ = task.result {
        // Do something with uploadTask.
    }

    return nil;
}

我收到以下 2 个错误。

无法在当前上下文中推断闭包参数“错误”的类型。无法在当前上下文中推断闭包参数“任务”的类型