message: QNS qlog
  Write qlog file to a directory specified by QLOGDIR environment variable
diff: @@ -481,6 +481,10 @@ fn main() -> Res<()> {
  Ok(_) => exit(127),
  Err(_) => exit(1),
  }
  +
  + if let Ok(qlogdir) = env::var("QLOGDIR") {
  + args.qlog_dir = Some(PathBuf::from(qlogdir));
  + }
  }
  let mut urls_by_origin: HashMap<Origin, Vec<Url>> = HashMap::new();
  