typedef NS_ENUM(NSUInteger, AIFURLResponseStatus)
{
AIFURLResponseStatusSuccess, //作为底层，请求是否成功只考虑是否成功收到服务器反馈。至于签名是否正确，返回的数据是否完整，由上层的RTApiBaseManager来决定。
AIFURLResponseStatusErrorTimeout,
AIFURLResponseStatusErrorNoNetwork // 默认除了超时以外的错误都是无网络错误。
};

NSURLSessionDataTask *task = [self.sessionManager dataTaskWithRequest:request completionHandler:^(NSURLResponse * _Nonnull response, id _Nullable responseObject, NSError * _Nullable error) {

    NSURLSessionDataTask *storedTask = self.dispatchTable[requestId];
    if (storedTask == nil) {
        // 如果这个operation是被cancel的，那就不用处理回调了。
        return;
    }else{
        [self.dispatchTable removeObjectForKey:requestId];
    }
    NSString *responseString = [[NSString alloc] initWithData:responseObject encoding:NSUTF8StringEncoding];
    
    if (!error) {
        
        // success
        
        [AIFLogger logDebugInfoWithResponse:(NSHTTPURLResponse*)response
                              resposeString:responseString
                                    request:request
                                      error:NULL];
        
        AIFURLResponse *response = [[AIFURLResponse alloc] initWithResponseString:responseString
                                                                        requestId:requestId
                                                                          request:request
                                                                     responseData:responseObject
                                                                           status:AIFURLResponseStatusSuccess];
        success?success(response):nil;
    }else{
        [AIFLogger logDebugInfoWithResponse:(NSHTTPURLResponse*)response
                              resposeString:responseString
                                    request:request
                                      error:error];

        AIFURLResponse *response = [[AIFURLResponse alloc] initWithResponseString:responseString
                                                                        requestId:requestId
                                                                          request:request
                                                                     responseData:responseObject
                                                                            error:error];
         fail?fail(response):nil;
    }
}];

//作为底层，请求是否成功只考虑是否成功收到服务器反馈。至于签名是否正确，返回的数据是否完整，由上层的RTApiBaseManager来决定。