make a note to improve stream timeout error handling

lib/storage/file.js

@@ -105,6 +105,9 @@ in the meantime. Used to prevent file descriptor leaks in the case of
 abandoned streams while closing streams which are being read very very
 slowly.
 
+XXX inform the stream consumer when it has been closed prematurely
+by calling back with a TIMEOUT error or something
+
 */
 const createIdleStreamCollector = function (stream) {
     // create a function to close the stream which takes no arguments