"Mask" string type response for API

[IamGrimbo]

Hi there, I am trying to get your PremTools work in my mobile application made in Unity, therefore all codes are written in C#. But I have no idea what should I do about required response parameter called "Mask". I firstly generated an image based of a prompt and then I am trying to remove background of that image. Generating image itself works, so I am stuck at removing the background part, which is why I am here. This is how my code looks like if it will help:

IEnumerator GenerateTransparentAsync(Texture2D texture2D)
{

    // Set the model parameters
    yield return sdc.SetModelAsync(modelsList[selectedModel]);
    
    // Generate the image
    HttpWebRequest httpWebRequest = null;

    try
    {
        // Make a HTTP POST request to the Stable Diffusion server
        httpWebRequest = (HttpWebRequest)WebRequest.Create(sdc.settings.StableDiffusionServerURL + sdc.settings.PbremPredictAPI);
        httpWebRequest.ContentType = "application/json";
        httpWebRequest.Method = "POST";

        // Send the generation parameters along with the POST request
        using (var streamWriter = new StreamWriter(httpWebRequest.GetRequestStream()))
        {
            byte[] inputImgBytes = texture2D.EncodeToPNG();
            string inputImgString = Convert.ToBase64String(inputImgBytes);

            SDPremPredict sd = new SDPremPredict();
            sd.img = inputImgString;

            // Serialize the input parameters
            string json = JsonConvert.SerializeObject(sd);

            // Send to the server
            streamWriter.Write(json);
        }
    }
    catch (Exception e)
    {
        Debug.LogError(e.Message + "\n\n" + e.StackTrace);
    }
    // Read the output of generation
    if (httpWebRequest != null)
    {
        // Wait that the generation is complete before procedding
        Task<WebResponse> webResponse = httpWebRequest.GetResponseAsync();

        while (!webResponse.IsCompleted)
        {
            if (sdc.settings.useAuth && !sdc.settings.user.Equals("") && !sdc.settings.pass.Equals(""))
                UpdateGenerationProgressWithAuth();
            else
                UpdateGenerationProgress();

            yield return new WaitForSeconds(0.5f);
        }

        // Stream the result from the server
        var httpResponse = webResponse.Result;

        using (var streamReader = new StreamReader(httpResponse.GetResponseStream()))
        {
            // Decode the response as a JSON string
            string result = streamReader.ReadToEnd();

            // Deserialize the JSON string into a data structure
            SDResponsePremPredict json = JsonConvert.DeserializeObject<SDResponsePremPredict>(result);

            // If no image, there was probably an error so abort
            if (json.img == null || json.img.Length == 0)
            {
                generating = false;
                yield break;
            }

            // Decode the image from Base64 string into an array of bytes
            byte[] imageData = Convert.FromBase64String(json.img);

            // Write it in the specified project output folder
            using (FileStream imageFile = new FileStream(filename, FileMode.Create))
            {
                yield return imageFile.WriteAsync(imageData, 0, imageData.Length);
                NativeGallery.SaveImageToGallery(filename, Application.productName + " Captures", name);

                AssetDatabase.StopAssetEditing();
                AssetDatabase.SaveAssets();
            }
            try
            {
                // Read back the image into a texture
                if (File.Exists(filename))
                {
                    texture = new Texture2D(2, 2);
                    texture.LoadImage(imageData);
                    texture.Apply();

                    LoadIntoMaterial(texture);
                    generatingFinished = true;
                }
            }
            catch (Exception e)
            {
                Debug.LogError(e.Message + "\n\n" + e.StackTrace);
            }
        }
    }
    generating = false;
    yield return null;

}