var async = require('async');

sum = function(x, y) {
  return (x + y)
}

x = 2;
y = 3;

async.parallel([
    function(callback) {
      setTimeout(function() {
        result = sum(x, y);
        callback(null, result);
      }, 100);
    },
    function(callback) {
      result = sum(x, y);
      callback(null, result);
    }

  ],

  function(err, results) {
    console.log(results[0] + results[1]);
  }
);