Microsoft.Extensions.Http


services
  .AddHttpClient(
   string name,
    Action<HttpClient> configureClient
  )
  .ConfigurePrimaryHttpMessageHandler(
    Func<HttpMessageHandler> configureHandler
  )
  .SetHandlerLifetime(TimeSpan handlerLifetime)

Использование IHttpClientFactory для реализации устойчивых HTTP-запросов
https://docs.microsoft.com/ru-ru/dotnet/architecture/microservices/implement-resilient-applications/use-httpclientfactory-to-implement-resilient-http-requests

YOU'RE USING HTTPCLIENT WRONG AND IT IS DESTABILIZING YOUR SOFTWARE
https://www.aspnetmonsters.com/2016/08/2016-08-27-httpclientwrong/