An alternative class for the app’s localized resources

The previous example was defined in terms of the Dart intl
package. Developers can choose their own approach for managing
localized values for the sake of simplicity or perhaps to integrate
with a different i18n framework.

Complete source code for the minimal app.

In the below example, the DemoLocalizations class 
includes all of its translations directly in per language Maps.

In the minimal app the DemoLocalizationsDelegate is slightly
different. Its load method returns a SynchronousFuture
because no asynchronous loading needs to take place.

Using the Dart intl tools

Before building an API using the Dart intl package
you’ll want to review the intl package’s documentation.
Here’s a summary of the process
for localizing an app that depends on the intl package.