flutter zone vs future - flutter

Question

I read about Zone and have used Futures in many languages. I know about Event Loop and that Dart is single threaded. However, when I write following code I could not differentiate how differently it will work and when to use one over another.
What is the difference between zone and future?
For example here:
runZoned(() async {
// Do Something
}, onError: (e, stackTrace) {
print(e);
});
Vs
someAsyncCall().catchError((e) {
print(e);
});

Answer 1

Futures error handling
Zones
What is a Future
Edit 1: I used runZonedGuarded instaed runZoned because runZoned.onError is deprecated.
Flutter : 'onError' is deprecated on runZoned function
Hi! With runZoned you can basically Handling asynchronous errors that are commonly caused by futures (http request, etc). The concept is similar to a try-catch in synchronous code. With Future you cannot do that.
runZoned example:
runZonedGuarded(() {
_timerError();
}, (error, stack) {
print('Uncaught error runZoneGuard: $error');
});
resullt:
I/flutter (13567): Uncaught error runZoneGuard: asynchronous error
Future example:
someCall().then((value) {
_timerError();
}, onError: (value) {
print('Uncaught error onError: $value');
}).catchError((e) {
print('Uncaught error catchError: $e');
});
result:
E/flutter (13567): [ERROR:flutter/lib/ui/ui_dart_state.cc(198)] Unhandled Exception: asynchronous error
E/flutter (13567): #0 _MyHomePageState._timerError.<anonymous closure> (package:async_study/main.dart:60:7)
E/flutter (13567): #1 _rootRun (dart:async/zone.dart:1418:47)
E/flutter (13567): #2 _CustomZone.run (dart:async/zone.dart:1328:19)
E/flutter (13567): #3 _CustomZone.runGuarded (dart:async/zone.dart:1236:7)
E/flutter (13567): #4 _CustomZone.bindCallbackGuarded.<anonymous closure> (dart:async/zone.dart:1276:23)
E/flutter (13567): #5 _rootRun (dart:async/zone.dart:1426:13)
E/flutter (13567): #6 _CustomZone.run (dart:async/zone.dart:1328:19)
E/flutter (13567): #7 _CustomZone.bindCallback.<anonymous closure> (dart:async/zone.dart:1260:23)
E/flutter (13567): #8 Timer._createTimer.<anonymous closure> (dart:async-patch/timer_patch.dart:18:15)
E/flutter (13567): #9 _Timer._runTimers (dart:isolate-patch/timer_impl.dart:398:19)
E/flutter (13567): #10 _Timer._handleMessage (dart:isolate-patch/timer_impl.dart:429:5)
E/flutter (13567): #11 _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:192:12)
And the '_timerError()' method used to trhow a async error:
void _timerError() {
Timer.run(() {
throw "asynchronous error";
});
}