protected override TOut _Handle(TIn input)
 {
     throw new NotImplementedException();
 }
 private int?GetAge(TIn input) => input.Age;
 private string GetSurname(TIn input) => input.Surname;
 private string GetName(TIn input) => input.Name;
 private async Task <int?> GetAge(TIn input) => await
 Task.Delay(1000).ContinueWith(x => input.Age);
 private async Task <string> GetSurname(TIn input) =>
 await Task.Delay(1000).ContinueWith(x => input.Surname);