unnecessary_nullable_for_final_variable_declarations     
                  Type could be non-nullable.
Description
#The analyzer produces this diagnostic when a final field or variable has a nullable type but is initialized to a non-nullable value.
Example
#
                    The following code produces this diagnostic because the final variable i
                    has a nullable type (int?), but can never be null:
                  
                      dart
                      
                  final int? i = 1;
Common fixes
#Make the type non-nullable:
                      dart
                      
                  final int i = 1;