build method
Initialize a Notifier.
It is safe to use Ref.watch or Ref.listen inside this method.
If a dependency of this Notifier (when using Ref.watch) changes,
then build will be re-executed. On the other hand, the Notifier
will not be recreated. Its instance will be preserved between
executions of build.
If this method throws, reading this provider will rethrow the error.
Implementation
@override
ThemeMode build() {
final savedTheme = ref.read(storageServiceProvider).getString(_themeKey);
return ThemeMode.values.firstWhere(
(e) => e.name == savedTheme,
orElse: () => ThemeMode.system,
);
}