message: auto-tune and rate-limit are mutually exclusive
diff: @@ -353,6 +353,7 @@ pub fn initialize() -> App<'static, 'static> {
  .long("rate-limit")
  .value_name("RATE_LIMIT")
  .takes_value(true)
  + .conflicts_with("auto_tune")
  .help("Limit number of requests per second (per directory) (default: 0, i.e. no limit)")
  )
  .arg(
  