public RelayPushRegistrationServiceTests()
        {
            _globalSettings = new GlobalSettings();
            _logger         = Substitute.For <ILogger <RelayPushRegistrationService> >();

            _sut = new RelayPushRegistrationService(
                _globalSettings,
                _logger
                );
        }
        public RelayPushRegistrationServiceTests()
        {
            _globalSettings = new GlobalSettings();
            _httpFactory    = Substitute.For <IHttpClientFactory>();
            _logger         = Substitute.For <ILogger <RelayPushRegistrationService> >();

            _sut = new RelayPushRegistrationService(
                _httpFactory,
                _globalSettings,
                _logger
                );
        }