Upload file anonymously with C#

Uploader.cs

        private static async Task<string> UploadFile(byte[] bytes, string expiresParam = "1d", bool noIndexParam = true)
        {
            string res = null;
            try
            {
                using (var client = new HttpClient())
                using (var formData = new MultipartFormDataContent())
                {
                    formData.Add(new StringContent(noIndexParam.ToString()), "no_index");
                    formData.Add(new StringContent(expiresParam), "expires");
                    formData.Add(new ByteArrayContent(bytes), "file", Guid.NewGuid().ToString());
                    HttpResponseMessage response = await client.PostAsync("https://api.anonymousfiles.io/", formData);
                    if (response.IsSuccessStatusCode)
                        return await response.Content.ReadAsStringAsync();
                }
            }
            catch (Exception ex) 
            {
                //handle ex
            }

            return res;
        }