DistanceMatcher constructor Null safety

1. irte_engine
2. distance_matcher
3. DistanceMatcher
4. DistanceMatcher constructor

DistanceMatcher class

1. Constructors
2. DistanceMatcher
3. Properties
4. hashCode
5. hasListeners
6. initialized
7. isClosed
8. listeners
9. onDelete
10. onStart
11. runtimeType
12. type
13. Methods
14. $configureLifeCycle
15. addListener
16. addListenerId
17. checkRunMode
18. dispose
19. disposeId
20. isExpired
21. match
22. noSuchMethod
23. notifyChildrens
24. onClose
25. onInit
26. onReady
27. refresh
28. refreshGroup
29. removeListener
30. removeListenerId
31. toString
32. unitIsMetric
33. update
34. Operators
35. operator ==