private async void OnUpdate(object sender, EventArgs e)
 {
     Models.Devices.Device device = _devices[0];
     device.NameDevice += " [updated]";
     string content = JsonConvert.SerializeObject(device);
     await _client.PutAsync(Url + "/" + device.IdDevice, new StringContent(content, Encoding.UTF8, "application/json"));
 }
        private async void OnDelete(object sender, EventArgs e)
        {
            Models.Devices.Device device = _devices[0];
            await _client.DeleteAsync(Url + "/" + device.IdDevice);

            _devices.Remove(device);
        }
        private async void OnAdd(object sender, EventArgs e)
        {
            Models.Devices.Device device = new Models.Devices.Device {
                NameDevice = $"{DateTime.UtcNow}"
            };
            string content = JsonConvert.SerializeObject(device);
            await _client.PostAsync(Url, new StringContent(content, Encoding.UTF8, "application/json"));

            _devices.Insert(0, device);
        }