mindfart probably

protected override async void OnResume()
        {

            try
            {
                var License = Helpers.Settings.License;
                if (License != null)
                {
                    var LicenseTrimmed = License.Replace("/", "").Replace("\\", "").Replace('"', ' ').Trim();
                    var req = new RegistrationUpdate()
                    {
                        SerialKey = LicenseTrimmed
                    };
                    var stringc = new StringContent(JsonConvert.SerializeObject(req), Encoding.UTF8, "application/json");
                    var res = await RestManager.Instance.ExecuteRest("getKey", stringc);
                    if (res != null && res != "offline")
                    {
                        var resm = JsonConvert.DeserializeObject<RegistrationKey>(res);
                        if (resm.RegToken == "" || resm.RegToken != CrossFirebasePushNotification.Current.Token)
                        {
                            var request = new RegistrationUpdate()
                            {
                                RegToken = CrossFirebasePushNotification.Current.Token,
                                SerialKey = LicenseTrimmed
                            };
                            try
                            {
                                var stringContent = new StringContent(JsonConvert.SerializeObject(request), Encoding.UTF8, "application/json");
                                await RestManager.Instance.ExecuteRest("SetPushtoken", stringContent);
                            }
                            catch
                            {

                            }

                        }
                    }
                }
            }catch(Exception e)
            {
                Crashes.TrackError(e);
            }
        }