ciTimestamp function
YYYYMMDD-HHMMSS, the name of a run's log folder.
Implementation
String ciTimestamp(DateTime t) {
String two(int v) => v.toString().padLeft(2, '0');
return '${t.year}${two(t.month)}${two(t.day)}-'
'${two(t.hour)}${two(t.minute)}${two(t.second)}';
}