public async Task GetSupplierByID(DTO_Supplier token)
        {
            try
            {
                var response = await client.PostAsJsonAsync(string.Format(@URL + "GetSupplierByID"), token);

                response.EnsureSuccessStatusCode();
                Supplier = await response.Content.ReadAsAsync <DTO_Supplier>();
            }
            catch (Exception ex)
            {
            }
        }
        public async Task AddSupplier(DTO_Supplier token)
        {
            try
            {
                var response = await client.PostAsJsonAsync(string.Format(@"{0}{1}", URL, "AddSupplier"),
                                                            token);

                response.EnsureSuccessStatusCode();
                Supplier = await response.Content.ReadAsAsync <DTO_Supplier>();
            }
            catch (Exception e)
            {
                Console.Write(e.StackTrace);
            }
        }