QueryServiceBase constructor Null safety

1. spine_client
2. query_service.pbserver
3. QueryServiceBase
4. QueryServiceBase constructor

QueryServiceBase class

1. Constructors
2. QueryServiceBase
3. Properties
4. $json
5. $messageJson
6. hashCode
7. runtimeType
8. Methods
9. createRequest
10. handleCall
11. noSuchMethod
12. read
13. toString
14. Operators
15. operator ==