Providing data using zones

main.dart

/*
 * Providing data using zones
 * https://gist.github.com/PlugFox/d35b4beb298e62819152cd259d4f44ca
 * https://dartpad.dev/d35b4beb298e62819152cd259d4f44ca
 * Matiunin Mikhail <plugfox@gmail.com>, 03 June 2022
 */

import 'dart:async';

void main() {
  functionA(); // prints '<null>'
  runZoned<void>(
    () => functionA(), // prints 'Zone'
    zoneValues: <Object?, Object?>{
      #my.zone.key: 'Zone',
    },
  );
  functionA(); // prints '<null>'
}

Future<void> functionA() async {
  functionB();
}

Future<void> functionB() async {
  print(Zone.current[#my.zone.key] ?? '<null>');
}