download speed is 0

[shenfu1991]

when i run blow code ,log show download speed and remainingTime is 0,why?

TCBlobDownloadManager *sharedManager = [TCBlobDownloadManager sharedInstance];
    
    
    TCBlobDownloader *downloader =[sharedManager startDownloadWithURL:[NSURL URLWithString:@"http://ofqnohifh.bkt.clouddn.com/%E3%80%90%E9%98%BF%E5%8F%B6%E5%90%9B%E3%80%91%E6%81%8B%E7%88%B1%E5%BE%AA%E7%8E%AF%E4%B9%8B%E4%B8%89%E5%88%86%E9%92%9F%E5%B8%A6%E4%BD%A0%E6%B8%B8%E5%B2%B3%E9%98%B3.mp4"] customPath:nil firstResponse:^(NSURLResponse *response) {
        
    } progress:^(uint64_t receivedLength, uint64_t totalLength, NSInteger remainingTime, float progress) {
        
        NSLog(@"speed=%ld,remainingTime=%ld",downloader.speedRate,downloader.remainingTime);
        
    } error:^(NSError *error) {
        
    } complete:^(BOOL downloadFinished, NSString *pathToFile) {
        
    }];