RaceDayEvents constructor Null safety

1. irte_engine
2. race_day_events
3. RaceDayEvents
4. RaceDayEvents constructor

RaceDayEvents class

1. Constructors
2. RaceDayEvents
3. Properties
4. hashCode
5. runtimeType
6. Methods
7. noSuchMethod
8. toString
9. Operators
10. operator ==
11. Constants
12. init
13. raceDay
14. raceDayEnd
15. raceEnd
16. raceStart