async void Verify_OTP(System.Object sender, System.EventArgs e)
        {
            try
            {
                //var result = await _firebaseAuth.LinkWithPhoneNumberVerificationCodeAsync(entryOTP.Text);

                var result = await _firebaseAuth.SignInWithPhoneNumberVerificationCodeAsync(entryOTP.Text);

                if (result != null && result.Uid != null)
                {
                    //await DisplayAlert("Success", "Firebase User Uid:" + result.Uid +", Provider:"+result.ProviderInfos, "Okay");

                    await Navigation.PushModalAsync(new HomePage(result));
                }
            }
            catch (FirebaseException ex)
            {
                await DisplayAlert("Error", ex.Message, "Okay");
            }
            catch (Exception ex)
            {
                await DisplayAlert("Error", ex.Message, "Okay");
            }
        }
 public IObservable <Unit> SignInWithPhoneNumberVerificationCode(string verificationCode)
 {
     return(RunAuthTask(
                _firebaseAuth.SignInWithPhoneNumberVerificationCodeAsync(verificationCode),
                signOutWhenFailed: true));
 }