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Dart Async and Await


import 'dart:async';
Future main() async {
 var value = await _waitForValue();
 print("Here is the value: $value");
 //since _waitForValue() returns immediately if you un it without await you won't get the
 var errorValue = "not finished yet";
 print("Here is the error value: $value");// not finished yet
Future<int> _waitForValue() => new Future((){
 var n = 100000000;
 // Do some long process
 for (var i = 1; i <= n; i++) {
 // Print out progress:
 if ([n / 2, n / 4, n / 10, n / 20].contains(i)) {
 print("Not done yet...");
 // Return value when done.
 if (i == n) {
 return i;


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