CODE EXAMPLE FOR JAVASCRIPT

async queue.push

var q = async.queue(function (userService, callback) {
  console.log('Here you do your stuff with the userService object');
  console.log('Calling the callback function');
  callback(null, userService);
}, 1);

q.push(userService, function (err, userService) {
  console.log('finished processing ' + userService.name);
});