report missing bytes

lib/reader.js

@@ -247,7 +247,7 @@ function HlsStreamReader(src, options) {
 
           // FIXME: is this required? or already handled by http-get?
           if (!err && (totalBytes !== meta.size))
-            err = new Error('Invalid returned stream length');
+            err = new Error('Invalid returned stream length (req='+meta.size+', ret='+totalBytes+')');
 
           cb(err, totalBytes);
         }