public static String filenamePrefixFromOffset(long offset) {
        NumberFormat nf = NumberFormat.getInstance();
        nf.setMinimumIntegerDigits(20);
        nf.setMaximumFractionDigits(0);
        nf.setGroupingUsed(false);
        return nf.format(offset);
    }
Make log segment file name from offset bytes. All this does is pad out the offset number with zeros
so that ls sorts the files numerically.

@param offset The offset to use in the file name
@return The filename
storage/src/main/java/org/apache/kafka/storage/internals/log/LogFileUtils.java