using (var xmlReader = XmlReader.Create(filePath, new XmlReaderSettings() { Async = true }))
{
    var feedReader = new RssFeedReader(xmlReader);

    while(await feedReader.Read())
    {
        switch (feedReader.ElementType)
        {
            // Read category
            case SyndicationElementType.Category:
                ISyndicationCategory category = await feedReader.ReadCategory();
                break;

            // Read Image
            case SyndicationElementType.Image:
                ISyndicationImage image = await feedReader.ReadImage();
                break;

            // Read Item
            case SyndicationElementType.Item:
                ISyndicationItem item = await feedReader.ReadItem();
                break;

            // Read link
            case SyndicationElementType.Link:
                ISyndicationLink link = await feedReader.ReadLink();
                break;

            // Read Person
            case SyndicationElementType.Person:
                ISyndicationPerson person = await feedReader.ReadPerson();
                break;

            // Read content
            default:
                ISyndicationContent content = await feedReader.ReadContent();
                break;
        }
    }
}

var sw = new StringWriterWithEncoding(Encoding.UTF8);

using (XmlWriter xmlWriter = XmlWriter.Create(sw, new XmlWriterSettings() { Async = true, Indent = true }))
{
    var writer = new RssFeedWriter(xmlWriter);
      
    // Create item
    var item = new SyndicationItem()
    {
        Title = "Rss Writer Avaliable",
        Description = "The new Rss Writer is now available as a NuGet Package!",
        Id = "https://www.nuget.org/packages/Microsoft.SyndicationFeed.ReaderWriter",
        Published = DateTimeOffset.UtcNow
    };

    item.AddCategory(new SyndicationCategory("Technology"));
    item.AddContributor(new SyndicationPerson("test", "test@mail.com"));

    await writer.Write(item);
    xmlWriter.Flush();
}

class StringWriterWithEncoding : StringWriter
{
    private readonly Encoding _encoding;

    public StringWriterWithEncoding(Encoding encoding)
    {
        this._encoding = encoding;
    }

    public override Encoding Encoding {
        get { return _encoding; }
    }
}