extensions/do_on_first_event library

1. booked_utils package
2. documentation
3. extensions/do_on_first_event.dart

booked_utils package

1. Libraries
2. booked_utils
3. builders/bloc_pop_builder
4. builders/builders
5. extensions/do_on_first_event
6. extensions/extensions
7. transformers/chunk_transformer
8. transformers/transformers
9. typedefs/callback_widget_builder
10. typedefs/typedefs
11. widgets/value_notifier_listener
12. widgets/widgets
13. wrappers/stream_controller_wrapper
14. wrappers/value_notifier_wrapper
15. wrappers/wrappers