Nullability of reference types in type of parameter 'source' doesn't match overridden member.

Possible null reference return.

Argument of type 'Action<object>' cannot be used for parameter 'callback' of type 'Action<object?>' in 'CancellationTokenRegistration CancellationToken.Register(Action<object?> callback, object? state, bool useSynchronizationContext)' due to differences in the nullability of reference types.

Possible null reference assignment.

Non-nullable field 'currentValue' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the field as nullable.

Non-nullable field 'exception' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the field as nullable.

Non-nullable field 'continuation' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the field as nullable.

Non-nullable field 'context' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the field as nullable.

Cannot convert null literal to non-nullable reference type.