Add Basic authentication header to DD4T Rest Provider

Authentication headers

public class HttpClientAuthentication : DD4T.Providers.Rest.IHttpMessageHandlerFactory
    {
        public HttpMessageHandler CreatePipeline(HttpMessageHandler innerHandler)
        {
            return HttpClientFactory.CreatePipeline(innerHandler, new[] {
                new BasicAuthenticationHandler()
            });
        }
    }

    public class BasicAuthenticationHandler : DelegatingHandler
    {

        protected override System.Threading.Tasks.Task<HttpResponseMessage> SendAsync(
            HttpRequestMessage request,
            System.Threading.CancellationToken cancellationToken)
        {

            var credentials = string.Format("{0}:{1}", "myusername", "mypassword");

            var byteArray = System.Text.Encoding.ASCII.GetBytes(credentials);
            request.Headers.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Basic", Convert.ToBase64String(byteArray));


            return base.SendAsync(request, cancellationToken);
        }
    }