public static HttpClientHandler CreateHttpClientHandler([CanBeNull] IProxyConfig proxyConfig) { HttpClientHandler clientHandler = new HttpClientHandler { PreAuthenticate = false, UseDefaultCredentials = true, UseProxy = false }; if (proxyConfig?.IsValid() == true) { IWebProxy proxy = proxyConfig.CreateWebProxy(); if (proxy != null) { clientHandler.UseProxy = true; clientHandler.Proxy = proxy; clientHandler.UseDefaultCredentials = proxyConfig.UseDefaultCredentials; clientHandler.PreAuthenticate = proxyConfig.UseDefaultCredentials; } } return(clientHandler); }