Better design for custom geocoding proxy

CustomGeocodeProxyProvider.cs

    public class CustomGeocodeProxyProvider : IGeocodeProxyProvider
    {
        private Uri baseUri;

        public CustomGeocodeProxyProvider(string baseUrl)
        {
            baseUri = new Uri(baseUrl);
        }

        public HttpWebRequest CreateRequest(string url)
        {
            url = new UriBuilder(url)
            {
                Host = baseUri.Host,
                Port = baseUri.Port, 
                Scheme = baseUri.Scheme
            }.Uri.ToString();
            return WebRequest.CreateHttp(url);
        }
    }