SyncGeneratorHelper constructor Null safety

1. irte_engine
2. sync_generator_helper
3. SyncGeneratorHelper
4. SyncGeneratorHelper constructor

SyncGeneratorHelper class

1. Constructors
2. SyncGeneratorHelper
3. Properties
4. hashCode
5. runtimeType
6. Methods
7. noSuchMethod
8. toString
9. Operators
10. operator ==
11. Static methods
12. engineModelToSqlOrRest
13. enumFromSqlOrRest
14. enumToSqlOrRest
15. mapToSql
16. relationToRest
17. sqlOrRestToEngineModel