Returns an enumerator that iterates through the HttpHeaderValueCollection<T>.
Assembly: System.Net.Http (in System.Net.Http.dll)
This enumerator returns the keys of the collection as strings.The foreach statement of the C# language (for each in Visual Basic) hides the complexity of the enumerators. Therefore, using foreach is recommended, instead of directly manipulating the enumerator.
Enumerators can be used to read the data in the collection, but they cannot be used to modify the underlying collection.
Initially, the enumerator is positioned before the first element in the collection.