private async void btnUpload_Click(object sender, EventArgs e)
        {
            //in this we convert image in the pictureBox to memory stream --> byte array --> toBase64String

            MemoryStream ms = new MemoryStream();

            pictureBox1.Image.Save(ms, ImageFormat.Jpeg);
            byte[] a      = ms.GetBuffer();
            String output = Convert.ToBase64String(a);
            var    data   = new Image_Modal
            {
                Img = output
            };
            SetResponse response = await client.SetTaskAsync("Image/", data);

            Image_Modal results = response.ResultAs <Image_Modal>();
        }
        private async void btnView_Click(object sender, EventArgs e)
        {
            //convert base64String --> byte array --> memory stream --> bitemap

            FirebaseResponse response = await client.GetTaskAsync("Image/");

            Image_Modal image = response.ResultAs <Image_Modal>();

            byte[]       b  = Convert.FromBase64String(image.Img);
            MemoryStream ms = new MemoryStream();

            ms.Write(b, 0, Convert.ToInt32(b.Length));

            Bitmap bm = new Bitmap(ms, false);

            ms.Dispose();

            pictureBox1.Image = bm;
        }