5 Temel Unsurları için C# IEnumerator neden kullanmalıyız
This type parameter is covariant. That is, you can use either the type you specified or any type that is more derived. For more information about covariance and contravariance, see Covariance and Contravariance in Generics. DerivedEnumerators emanet be used to read the data in the collection, but they cannot be used to modify the underlying collect