QuantizerMap constructor Null safety

1. Flutter
2. quantizer_map
3. QuantizerMap
4. QuantizerMap constructor

QuantizerMap class

1. Constructors
2. QuantizerMap
3. Properties
4. hashCode
5. runtimeType
6. Methods
7. noSuchMethod
8. quantize
9. toString
10. Operators
11. operator ==