CircleUtils constructor Null safety

1. geometry_kit
2. geometry_kit
3. CircleUtils
4. CircleUtils constructor

CircleUtils class

1. Constructors
2. CircleUtils
3. Properties
4. hashCode
5. runtimeType
6. Methods
7. noSuchMethod
8. toString
9. Operators
10. operator ==
11. Static methods
12. area
13. isPointInsideCircle
14. perimeter