use actual file size in dl progress. detect cancelled stream

server/routes/metadata.js

@@ -4,12 +4,10 @@ module.exports = async function(req, res) {
   const id = req.params.id;
   const meta = req.meta;
   try {
-    const size = await storage.length(id);
     const ttl = await storage.ttl(id);
     res.send({
       metadata: meta.metadata,
       finalDownload: meta.dl + 1 === meta.dlimit,
-      size,
       ttl
     });
   } catch (e) {