generateUniqueId method
Implementation
String generateUniqueId() {
DateTime now = DateTime.now();
return "${now.year}${now.month.toString().padLeft(2, '0')}"
"${now.day.toString().padLeft(2, '0')}${now.hour.toString().padLeft(2, '0')}"
"${now.minute.toString().padLeft(2, '0')}${now.second.toString().padLeft(2, '0')}"
"${now.millisecond.toString().padLeft(3, '0')}";
}