build abstract 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
@visibleForOverriding
State build();