CreateAndInitHttpClient Basic auth

WTClient.cs

private HttpClient CreateAndInitHttpClient(IHttpClientFactory httpClientFactory, WorktribeClientConfig config)
        {
            if (httpClientFactory == null)
                throw new ArgumentNullException(nameof(httpClientFactory));
            if (string.IsNullOrWhiteSpace(config.BaseUrl))
                throw new ArgumentNullException("config.BaseUrl");
            if (string.IsNullOrWhiteSpace(config.Username))
                throw new ArgumentNullException("config.Username");
            if (string.IsNullOrWhiteSpace(config.Password))
                throw new ArgumentNullException("config.Password");

            var httpClient = httpClientFactory.CreateClient(Constants.WorktribeHttpClient);
            if (httpClient == null)
                throw new NullReferenceException("HttpClient");

            //basic auth
            var hash = Convert.ToBase64String(Encoding.UTF8.GetBytes($"{config.Username}:{config.Password}"));
            httpClient.DefaultRequestHeaders.Clear();
            httpClient.DefaultRequestHeaders.Add("Authorization", $"Basic {hash}");
            httpClient.DefaultRequestHeaders.TryAddWithoutValidation("Content-Type", "application/json");

            return httpClient;
        }