AFNetWorking实现代码延迟

dispatch_async(dispatch_get_global_queue(0, 0), ^{
                sleep(0);
                dispatch_async(dispatch_get_main_queue(), ^{
                    NSData* data=[html dataUsingEncoding:NSUTF8StringEncoding];
                    id diction = [NSJSONSerialization  JSONObjectWithData:data options:0 error:nil];
                    success(diction);
                    [withView hideActivityIndicator];
                });
            });