Initialize variable inside 'initState' or just below the class definition? [duplicate]

Question

I am wondering when I know the initial value to a variable in a State class in Flutter, whether I should initialize it with the variable definition or inside initState method. What is better and why?

First method:

class _SampleState extends State<Sample> {
  String _foo = 'FOO';

  @override
  void initState() {
    // Do some other stuff
    super.initState();
  }

  ...
}

Second method:

class _SampleState extends State<Sample> {
  String _foo;

  @override
  void initState() {
    _foo = 'FOO';
    // Do some other stuff
    super.initState();
  }

  ...
}

Answer 1

What I think is you can initially define it without using the initstate(), but if you assigning any value to it then there comes the initstate where you process some things like api calls or any other and then assign the value to it. For More details check out this link where Remi has explained :

is there any difference between assigning value to the variable inside of initState or not in Flutter StatefulWidget?