Is there any way to download attachements from HP QC through API with C#

Question

I had this code below to download attachments from HP QC through API with C#. I think that I succeeded to log in to HP QC through API but I had the following two issues:

• First, how should I do to ensure that I had connected successfully actually I am doing that by throwing a message box message that would be great if you had an additional method for that.

• Second, I didn't figure out a way to download the attachments from HP ALM reqs after being logged in (I think I am). I've seen in a lot of posts over the web but usually, I see examples of that using Otaclient.dll, unfortunately, I could not use that since I am not able to register mine due to lack of admin privileges. Is there any way for that?

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.IO;
using System.Net;
using System.Reflection;
using System.Net.Http;
using System.Net.Http.Headers;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Windows.Forms;
namespace WindowsFormsApplication1
{
    class Class3
    {
        public static void SetBasicAuthHeader(WebRequest request, String userName, String userPassword)
        {
            string authInfo = userName + ":" + userPassword; 
            authInfo = Convert.ToBase64String(Encoding.Default.GetBytes(authInfo));
            request.Headers["Authorization"] = "Basic " + authInfo;
        }

        static void Main(string[] args)
        {
            ServicePointManager.Expect100Continue = true;
            ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls
                | SecurityProtocolType.Tls11
                | SecurityProtocolType.Tls12
                | SecurityProtocolType.Ssl3;
            String ALMBASEURL = "ALM Server URL that ends with qcbin";   
            WebRequest request = WebRequest.Create(ALMBASEURL + "/api/authentication/sign-in");
            SetBasicAuthHeader(request, "userName", "userPassword");
            WebResponse response = request.GetResponse();
            HttpWebResponse ORES = (HttpWebResponse)response;
            if (ORES.StatusCode == HttpStatusCode.OK)
            {
                MessageBox.Show("Login is successful" ); 
                //I am here but @stackoverflow I need your help to bulk download HP ALM reqs attachements.
            }
            else
            {
                MessageBox.Show("Login NOT successful");
            }
        }
    }
}