private static @NotNull String formatInternetSpeed(long fileSize) {
    int rank = (int)((Math.log10(fileSize) + 0.0000021714778384307465) / 3);  // (3 - Math.log10(999.995))
    double value = fileSize / Math.pow(1000, rank);
    String[] units = {"Bit", "Kbit", "Mbit", "Gbit"};
    return new DecimalFormat("0.##").format(value) + units[rank] + "/s";
  }
private static @NotNull String formatInternetSpeed(long fileSize)