doctor property Null safety

1. farmershands
2. chat_list_subscreen_arguments
3. ChatListSubscreenArguments
4. doctor property

ChatListSubscreenArguments class

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