public static void AddQnaApiClient(this IServiceCollection services, QnaApiConfig config, bool disableBearerHeader = false)
 {
     config.DisableBearerHeader = disableBearerHeader;
     services.AddTransient <QnaApiConfig>(provider => config);
     services.AddHttpClient <QnaApiClient>(client => client.BaseAddress = config.BaseUri);
 }
        public QnaApiClient(HttpClient httpClient, QnaApiConfig apiConfig)
        {
            _httpClient = httpClient;

            _httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", apiConfig.GetBearerToken());
        }