This is an example of how you can manage busy states across the app.
BusyService is a singleton that stores BusyState objects.
These objects can be referred to by a string key through the BusyService so you can easily retrieve the same object in different parts of the application:
- They count activations and deactivations so they can be used concurrently.
- They can notify interested parties when their state changes.
This is a UI-component that wraps around the specific BusyState object and provides a simplified way of watching for busy state change notifications to other UI components.