// www.google.com resolves to 142.250.65.206
// but not to 8.8.8.8
var httpClient = new HttpClient();
var requestUri = new Uri("https://8.8.8.8/");
var request = new HttpRequestMessage(HttpMethod.Get, requestUri);
request.Headers.TryAddWithoutValidation("host", "www.google.com");
var response = await httpClient.SendAsync(request);

// This produces WebException: The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel.