Converting null literal or possible null value to non-nullable type.

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

Dereference of a possibly null reference.

Dereference of a possibly null reference.

Dereference of a possibly null reference.

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

Dereference of a possibly null reference.

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

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