private TopicTree Read(DirectoryPath root, Stream stream)
{
var result = new List<TopicSection>();
var reader = new XmlTextReader(stream);
while (reader.Read())
{
if (reader.IsStartElement() && reader.Name == "section")
{
var section = ReadSection(reader, root);
if (section != null)
{
result.Add(section);
}
}
}
return new TopicTree(result);
}