1. Dart
2. dart:html
3. MediaKeySession
4. expiration property

##### MediaKeySession class

1. Properties
2. closed
3. expiration
4. hashCode
5. keyStatuses
6. on
7. onMessage
8. runtimeType
9. sessionId
10. Methods
11. addEventListener
12. close
13. dispatchEvent
14. generateRequest
15. load
16. noSuchMethod
17. remove
18. removeEventListener
19. toString
20. Operators
21. operator ==
22. Constants
23. messageEvent

description

# expiration property Null safety

num? expiration

## Implementation

    num? get expiration native;