How to use System.Net.Http.HttpClient to create new RT(request tracker ticket)

Need to develop a C# application to create new RT tickets, but the example code for c# on https://rt-wiki.bestpractical.com/wiki/REST#C.23 is not working.

I have found information from different places but none of them really have example on how to create a new rt ticket by using C# HttpClient.

Here is my attempt:

private static async void HTTP_Create()
{
        HttpClient client = new HttpClient();
        client.BaseAddress = new Uri(baseURL);

        string ticketUri = string.Format("REST/1.0/ticket/new?user={0}&pass={1}", testUser.UserName, testUser.Password);

        // Doesn't work
        var TicketDataContent = new List<KeyValuePair<string, string>>();
        TicketDataContent.Add(new KeyValuePair<string, string>("id", "ticket/new"));
        TicketDataContent.Add(new KeyValuePair<string, string>("Queue", "queue name"));
        TicketDataContent.Add(new KeyValuePair<string, string>("Requestor", "name@email.com"));
        TicketDataContent.Add(new KeyValuePair<string, string>("Owner", "owner@email.com)"));
        TicketDataContent.Add(new KeyValuePair<string, string>("Subject", "Created by C#"));
        TicketDataContent.Add(new KeyValuePair<string, string>("Text", "Ticket body with messages related to this ticket"));

        var ticketContent = new MultipartFormDataContent();
        ticketContent.Add(new FormUrlEncodedContent(TicketDataContent), "content");
        var response = await client.PostAsync(baseURL + ticketUri, ticketContent);

        Console.WriteLine("Response StatusCode: " + response.StatusCode.ToString());

        var retContent = response.Content;
        var retMsg = await response.Content.ReadAsStringAsync();

        Console.WriteLine(retMsg);
}

I got the following response:

Response StatusCode: OK

RT/4.4.2 200 Ok

# Required: id, Queue

Any help is appreciated. Thanks!