Scheduling tasks using Futures

The Dart VM is single-threaded, so all of an app's code runs in one thread, also called the main isolate. This is because main() is the function where Dart code starts executing an isolate, because Dart's concurrency model is based on isolates as separate processes that exchange messages. We will talk about isolates in depth in the coming recipes, but if your code doesn't start a new isolate, all of it runs in one isolate. But, in this one isolate, you can have lots of asynchronous pieces of code (let's call them tasks) running at the same time; in what order do they execute, and can we influence that order? It turns out that a better understanding of Dart's event loop and task queuing mechanism enables us to do that. This recipe will clarify Dart's scheduling mechanism and give you hints and tips for an ordered execution of tasks.

How to do it...

Have a look at the program tasks_scheduling.dart (the tasks are numbered consecutively and according to the way they...