public async Task <string> GetAuthToken()
        {
            using (System.Net.Http.HttpClient httpClient = ClientBuilder
                                                           .Create(_baseUri)
                                                           .WithHandler(innerHandler => new LoggingHandler(_loggerFactory, innerHandler))
                                                           .Build())
            {
                SessionResponse response = await httpClient
                                           .MakeSession(_username, _password, _serialNumber)
                                           .ConfigureAwait(false);

                return(response.SecurityToken);
            }
        }