public async Task<IEnumerable<Actor>> GetActorsBySeriesIdAsync(string seriesId)
{
if (seriesId == null) throw new ArgumentNullException(nameof(seriesId));
var url = $"{this.allMirror.RandomTake().MirrorPath}/api/{this.apiKey}/series/{seriesId}/actors.xml";
var request = WebRequest.CreateHttp(url);
var result = (await request.GetResultAsBytesAsync()).AsXml<ActorArray>();
return result.IsSuccess && result.Result.Actors != null
? result.Result.Actors
: Enumerable.Empty<Actor>();
}