private static async Task <string> BuildAtomFeed( DateTimeOffset lastUpdate, PagedQueryable <MunicipalitySyndicationQueryResult> pagedMunicipalities, IOptions <ResponseOptions> responseOptions, IConfiguration configuration) { var sw = new StringWriterWithEncoding(Encoding.UTF8); using (var xmlWriter = XmlWriter.Create(sw, new XmlWriterSettings { Async = true, Indent = true, Encoding = sw.Encoding })) { var formatter = new AtomFormatter(null, xmlWriter.Settings) { UseCDATA = true }; var writer = new AtomFeedWriter(xmlWriter, null, formatter); var syndicationConfiguration = configuration.GetSection("Syndication"); var atomConfiguration = AtomFeedConfigurationBuilder.CreateFrom(syndicationConfiguration, lastUpdate); await writer.WriteDefaultMetadata(atomConfiguration); var municipalities = await pagedMunicipalities.Items.ToListAsync(); var highestPosition = municipalities.Any() ? municipalities.Max(x => x.Position) : (long?)null; var nextUri = BuildNextSyncUri( pagedMunicipalities.PaginationInfo.Limit, highestPosition + 1, syndicationConfiguration["NextUri"]); if (nextUri != null) { await writer.Write(new SyndicationLink(nextUri, GrArAtomLinkTypes.Next)); } foreach (var municipality in municipalities) { await writer.WriteMunicipality(responseOptions, formatter, syndicationConfiguration["Category"], municipality); } xmlWriter.Flush(); } return(sw.ToString()); }