如何将UIDocumentPickerViewcontroller文件上传到亚马逊S3 TransferUtility Swift

import AWSS3

// 在AppDelegate中配置AWS
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
    let credentialsProvider = AWSStaticCredentialsProvider(accessKey: "YOUR_ACCESS_KEY", secretKey: "YOUR_SECRET_KEY")
    let configuration = AWSServiceConfiguration(region: .USEast1, credentialsProvider: credentialsProvider)
    AWSServiceManager.default().defaultServiceConfiguration = configuration
    return true
}

// 在需要上传文件的地方调用以下代码
func uploadFileToS3(fileURL: URL) {
    let transferUtility = AWSS3TransferUtility.default()
    
    let uploadExpression = AWSS3TransferUtilityUploadExpression()
    uploadExpression.progressBlock = { (task, progress) in
        // 上传进度回调
        print("Upload progress: \(progress.fractionCompleted)")
    }
    
    let completionHandler = { (task, error) -> Void in
        // 上传完成回调
        if let error = error {
            print("Upload failed with error: \(error.localizedDescription)")
        } else {
            print("Upload completed successfully.")
        }
    }
    
    transferUtility.uploadFile(fileURL, bucket: "YOUR_BUCKET_NAME", key: "YOUR_FILE_NAME", contentType: "YOUR_CONTENT_TYPE", expression: uploadExpression, completionHandler: completionHandler).continueWith { (task) -> Any? in
        if let error = task.error {
            print("Upload failed with error: \(error.localizedDescription)")
        }
        if let _ = task.result {
            // 上传成功
        }
        return nil
    }
}