用于POST的AFNetworking 2.0自定义标头

我正在尝试使用自定义标头执行POST请求,但我不断收到此异常和应用程序失败:

'NSUnknownKeyException', reason: '[ setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key X-Auth-AID.'

我已按照GitHub上代码论坛的说明操作:

这两个

AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];
AFHTTPRequestSerializer *requestSerializer = [AFHTTPRequestSerializer serializer];
[requestSerializer setValue:@"test" forKey:@"X-Auth-AID"];
manager.requestSerializer = requestSerializer;

还有这个:

AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];
[manager.requestSerializer setValue:@"test" forKey:@"X-Auth-AID"];

抛出异常......