如何从NSURLSessionDataTask获取状态代码？

在NSURLSessionDataTask有response可转换为一个属性NSHTTPURLResponse来获取状态代码:

Swift示例:

if let urlResponse = sessionDataTask.response as? NSHTTPURLResponse {
    let status = urlResponse.statusCode
}

Objective-C示例:

NSInteger statusCode = 0;

if ([sessionDataTask.response isKindOfClass:[NSHTTPURLResponse class]]) {
    NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *)sessionDataTask.response;
    statusCode = httpResponse.statusCode;
}