FeedReader: 最初の実装 ～ 同期処理だったらこんな感じ

FeedReader.cs

private /* async Task< */FeedData/* > */ Read/* Async */(Uri feedUri)
{
    SyndicationClient client = new SyndicationClient() { BypassCacheOnRetrieve = true };
    SyndicationFeed feed = /* await */ client.RetrieveFeed/* Async */(feedUri);

    return feed.ToFeedData();
}