https://learn.microsoft.com/ru-ru/dotnet/api/system.net.http.delegatinghandler?view=netframework-4.8.1&viewFallbackFrom=net-10.0
DelegatingHandler Class (System.Net.Http) | Microsoft Learn
A type for HTTP handlers that delegate the processing of HTTP response messages to another handler, called the inner handler.
class systemhttpmicrosoftlearn