add datetime and time dart flutter code example

Example: flutter date time

var now = new DateTime.now();
var moonLanding = DateTime.parse(now);

moonLanding.year; 
moonLanding.hour;  
moonLanding.month; 

moonLanding.year.toString() + '-' + moonLanding.month.toString() + '-' + moonLanding.day.toString()

############################ OR ###########################

import 'package:intl/intl.dart';

var dt = DateTime.now();
var newFormat = DateFormat("yy-MM-dd");
String updatedDt = newFormat.format(dt);
print(updatedDt); // 20-04-03

var newDt = DateFormat.yMMMEd().format(dt);
print(newDt);  // Fri, Apr 3, 2020

reference :
https://medium.com/flutter-community/working-with-dates-in-dart-e81c70911811