Read timestamp when scanner started

    log.info('Mean bandwidth per line: %f "KiB"', bw_per_line)

def read_started_ts(conf):

    """Write timestamp in Unix Epoch seconds.microsecs when scanner started.

    :param ConfigParser conf: configuration

    """

    with open(os.path.join(conf['paths']['datadir'],

                           conf['scanner']['started_filepath']), 'wt') as fd:

        scanner_started_ts = fd.read()

    return scanner_started_ts

def main(args, conf):

    if not is_initted(args.directory):

        fail_hard('Sbws isn\'t initialized.  Try sbws init')

    data_lines = [result_data_to_v3bw_line(results, fp) for fp in results]

    data_lines = sorted(data_lines, key=lambda d: d.bw, reverse=True)

    data_lines = scale_lines(args, data_lines)

    header = V3BwHeader()

    scanner_started_ts = read_started_ts(conf)

    header = V3BwHeader(earlier_result_ts=earlier_result_ts,

                        scanner_started_ts=scanner_started_ts)

    log_stats(data_lines)

    output = conf['paths']['v3bw_fname']

    if args.output: