data property Null safety

1. baguette
2. CalendarMarker
3. CalendarMarker
4. data property

CalendarMarker class

1. Constructors
2. CalendarMarker
3. Properties
4. data
5. endDate
6. hashCode
7. label
8. mode
9. runtimeType
10. startDate
11. Methods
12. noSuchMethod
13. split
14. toString
15. Operators
16. operator ==