Преобразование HttpResponseMessage в XML в объект

Я определил сериализацию для своего объекта idAssignmentResult. Но как мне преобразовать HttpResponseMessage, который IS XML, в его класс? Я получаю сообщение об ошибке:

Значение типа «System.Net.Http.HttpContent» не может быть преобразовано в «System.Xml.XmlReader».

Я буду делать и vb.net, и c#

vb.net

    Dim response As New HttpResponseMessage()
        Try
            Using client As New HttpClient()
                Dim request As New HttpRequestMessage(HttpMethod.Post, "url")
                request.Content = New StringContent(stringWriter.ToString, Encoding.UTF8, "application/xml")

                response = client.SendAsync(request).Result
            End Using
        Catch ex As Exception
            lblerror.Text = ex.Message.ToString
        End Try
    Dim responseString = response.Content

    Dim xmls As New XmlSerializer(GetType(idAssignmentResult))
    Dim assignmentResult As New idAssignmentResult()
    xmls.Deserialize(responseString, assignmentResult) /// cannot convert HttpContent to XmlReader

c#

    StringWriter stringWriter = new StringWriter();
    XmlSerializer serializer = new XmlSerializer(typeof(personV3R));
    personV3R person = new personV3R(); serializer.Serialize(stringWriter, person);
    HttpResponseMessage response = new HttpResponseMessage();
    try
    {
        using (HttpClient client = new HttpClient())
        {
            HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Post, "url");
            request.Content = new StringContent(stringWriter.ToString, Encoding.UTF8, "application/xml");
            response = client.SendAsync(request).Result;
        }
    }
    catch (Exception ex)
    {
        lblerror.Text = ex.Message.ToString;
    }

    var responseString = response.Content;

    XmlSerializer xmls = new XmlSerializer(typeof(idAssignmentResult));
    idAssignmentResult assignmentResult = new idAssignmentResult();
    xmls.Deserialize(responseString, assignmentResult);