//advance the parser in chunks until the given node is complete
static void AdvanceUntilClosed(XObject ob, XmlParser parser, IReadonlyTextDocument document)
{
const int chunk = 200;
var el = ob as XElement;
while (parser.Position < document.Length)
{
parser.Parse(document.CreateReader(parser.Position, Math.Min(document.Length - parser.Position, chunk)));
if (el?.IsClosed ?? ob.IsEnded || !parser.Nodes.Contains(ob.Parent))
{
break;
}
}
}