/// <summary>
 /// search code
 /// http://developer.github.com/v3/search/#search-code
 /// </summary>
 /// <param name="search"></param>
 /// <returns>List of files</returns>
 public IObservable <SearchCodeResult> SearchCode(SearchCodeRequest search)
 {
     Ensure.ArgumentNotNull(search, nameof(search));
     return(_client.SearchCode(search).ToObservable());
 }