protected void OnCustomerAdded(CustomerAddedEvent e)
{
_firstName = e.FirstName;
_lastName = e.LastName;
_age = e.Age;
_email = e.Email;
}
public Customer(string firstName, string lastName, int age, string email)
{
var e = new CustomerAddedEvent {Age = age, Email = email, FirstName = firstName, LastName = lastName};
ApplyEvent(e);
}