private static @Nullable String calculateFileName(@NotNull SystemOpsStatistic systemOpsStatistic) {
    long connectionSpeed = systemOpsStatistic.getConnectionSpeedBytesPerSec();
    if (connectionSpeed > 3_000_000) return "75_MB.dat";
    if (connectionSpeed > 2_000_000) return "50_MB.dat";
    if (connectionSpeed > 1_300_000) return "25_MB.dat";
    if (connectionSpeed > 700_000) return "10_MB.dat";
    return null;
  }
private static @Nullable String calculateFileName(@NotNull SystemOpsStatistic systemOpsStatistic)