Hopefully-temp fix for windos

lib/storage.js

@@ -38,6 +38,10 @@ storage.ensureFileDoesntExist = function (file, callback) {
  *  Flush data in OS buffer to storage if corresponding option is set
  */
 storage.flushToStorage = function (filename, callback) {
+  // Hate having to do this but I can't seem to make fs.fsync work on Windows, and still don't even know whether fsync can be used on Windows.
+  // See this issue: https://github.com/nodejs/node/issues/3879
+  if (process.platform === 'win32' || process.platform === 'win64') { return callback(); }
+
   fs.open(filename, 'r', function (err, fd) {
     if (err) { return callback(err); }
     fs.fsync(fd, function (err) { return callback(err); });