private async Task <AuthenticationResult> GetAuthenticationResultAsync()
        {
            AuthenticationResult authenticationResult;

            try
            {
                // Try to get the tokens silently.
                authenticationResult = await _authenticationService.AcquireTokenSilentAsync();

                return(authenticationResult);
            }
            catch
            {
                // Ignored.
            }

            // Prompt the user.
            authenticationResult = await _authenticationService.AcquireTokenAsync();

            return(authenticationResult);
        }