SensorState constructor Null safety

1. farmershands
2. sensor_state
3. SensorState
4. SensorState constructor

SensorState class

1. Constructors
2. SensorState
3. Properties
4. hashCode
5. hasListeners
6. runtimeType
7. sensors
8. Methods
9. addListener
10. dispose
11. fetchSensors
12. noSuchMethod
13. notifyListeners
14. removeListener
15. toString
16. Operators
17. operator ==