Exercise 11 gives seemingly nonsense error

[ghost]

My original solution to exercise 11 didn't pipe the filestream to the output. Instead it read the file into a variable and then served it. The solution was rejected for a most unhelpful reason:

Used fs method other than fs.createReadStream(): fs.createReadStream()

You probably want to change this to something more informative.

The entire problematic solution is below. Again, I don't need help solving the exercise, I'm just informing you of the weird error message.

var http = require('http')
var fs = require('fs')

var port = process.argv[2];
var path = process.argv[3];
var file = ""
var filestream = fs.createReadStream(path, function(err, chunk){
  file += chunk;
})

http.createServer(function (res, rep) {
  rep.end(file);
}).listen(port)