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samples/isolate_example/README.md

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# Isolate Example
A sample application that demonstrate best practices when using [`isolates`](https://api.dartlang.org/stable/2.3.1/dart-isolate/Isolate-class.html).
## Goals
* Display the performance benefits of isolates when using them in the right situation.
* Show how to use the `compute` method for straightforward computations.
* Demonstrate how to initialize and use an isolate.
* Show the cost of moving data between isolates and provide alternatives.
## The important bits
### `page_one.dart`
Compares running a large computation on the main isolate with running the same calculation
on a second isolate. When the main isolate is used, Flutter is unable to render new frames, and
the `SmoothAnimationWidget`'s animation freezes.
### `page_two.dart`
Creates an isolate used to run an infinite loop that sums batches of 100M randomly generated
numbers at a time. Users can start, terminate, pause, and resume the isolate, as well as modify
how the calculation is performed.
### `page_three.dart`
Demonstrates how expensive it is to move large amounts of data between isolates and a
better alternative to move data. This page creates an isolate that can add up a list of numbers
and gives users three options for how to provide it with input:
* Send values normally using a List
* Send the values using TransferableTypedData
* Generate the values on the second isolate, so no copying is necessary
Users can then compare the performance of each approach using the displayed timestamps.
## Questions/issues
If you have a general question about any of the techniques you see in
the sample, the best places to go are:
* [The FlutterDev Google Group](https://groups.google.com/forum/#!forum/flutter-dev)
* [The Flutter Gitter channel](https://gitter.im/flutter/flutter)
* [StackOverflow](https://stackoverflow.com/questions/tagged/flutter)
If you run into an issue with the sample itself, please file an issue
in the [main Flutter repo](https://github.com/flutter/flutter/issues).