-(void)function{
    Request *request = [[Request alloc] init];
    __block Api *api = [[Api alloc] initWithRequest:request];
    __block void(^responseListener)(NSURLSessionDataTask*,id);
    void(^responseListener_)(NSURLSessionDataTask*,id) = ^(NSURLSessionDataTask *task, id responseObject){
        [api request];
    };
    responseListener = responseListener_;
    api.responseListener = responseListener;
    [api request]; //裡面是AFNetworking的相關實作 大概就是 [AFHTTPSessionManager POST:xxx..略..success:(api.responseListener)];
}