Create an event with an attachment on Calendar via Google apps script

I couldn't find a way to add an attachment to my calendar event. I hope there should be a simple way like below snippet,

function createNewEvent()
{
 var file = DriveApp.getFileById('1eqaThzYmTbZzP-my file id-rXrBrWDW8DwMNeU');   //get file to be attached
 var title  = 'Apollo 11 Landing';
 var startTime = new Date('January 20, 2016 20:00:00 UTC');
 var endTime = new Date('January 20, 2016 21:00:00 UTC');
 var options = {description:'Sample description', location: 'The Moon', attachments:file}; //can we add attachments like this?

 var event = CalendarApp.getDefaultCalendar().createEvent(title, startTime, endTime, options);
}

Is this possible?

Yes, this is possible. First you must enable the Advanced Calendar Service. Then you can do something like this:

function createNewEvent() {
  var calendarId = ''; //Calendar Id String
  var fileId = ''; // File Id String
  var start = new Date('January 20, 2016 20:00:00 UTC');
  var end = new Date('January 20, 2016 21:00:00 UTC');
  var eventObj = {
    summary: 'Apollo 11 Landing',
    location: 'The Moon',
    description: 'Sample description',
    start: {dateTime: start.toISOString()},
    end: {dateTime: end.toISOString()},
    attachments: [{
        'fileUrl': 'https://drive.google.com/open?id=' + fileId,
        'title': 'Moon Docs'
    }]
  };
  var resp = Calendar.Events.insert(eventObj, calendarId, {'supportsAttachments': true});
  Logger.log(resp); // Check out the response in the logs!
}

For more options, check out the Events documentation.