Swift: Escaping closure captures non-escaping parameter 'onCompletion'

遇到一个编译报错：

Escaping closure captures non-escaping parameter 'onCompletion'

代码如下：

func fetchRecentPhotos(completion: (PhotosResult) -> Void)
    {
        let url = recentPhotosURL()
        let request = URLRequest(url: url as URL)
        let task = session.dataTask(with: request)
        {
            (data, response, error) -> Void in
            
            let result = self.processRecentPhotosRequest(data: data as NSData?, error: error as NSError?)
            completion(result)
        }
        task.resume()
    }

　这是由于completion导致的，默认闭包completion是@nonescaping的,只需要声明成@escaping即可。

func fetchRecentPhotos(completion: @escaping (PhotosResult) -> Void)