How to save response of the Get File Archive api

Trying to pull an archive of my public repo using this api:
GET /projects/:id/repository/archive

Here’s the url:
https://gitlab.com/api/v4/projects//repository/archive.zip

Here’s my C# code:
using (HttpClient httpClient = new HttpClient())
{
httpClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue(“application/json”));

                var response = httpClient.GetAsync(url);
                var httpContent = response.Result.Content;
                return httpContent.ReadAsStringAsync();
            }

When I save the response string to a disk file, I am unable to open it. Windows 10 reports that it is not a valid zip file. Perhaps I need to “massage” the response string first before saving? I have tried saving it with File.WriteAllText(), File.WriteAllBytes() and FileStream.Write(), but nothing works.

Would appreciate some pointers from the forum.