Race condition when using async.times

[kp96]

When I tested the limiter with the code below

var redis = require('ioredis'),
  Limiter = require('ratelimiter'),
  async = require('async'),
  db = redis.createClient(),
  limiter;

limiter = new Limiter({
  id: 'hello',
  db: db
});

async.times(10, function(n, next) {
  limiter.get(next);
}, function(err, res) {
  console.log(res);
});

It printed the following

[ { total: 2500, remaining: 2500, reset: 1485859856 },
  { total: 2500, remaining: 2499, reset: 1485859856 },
  { total: 2500, remaining: 2499, reset: 1485859856 },
  { total: 2500, remaining: 2499, reset: 1485859856 },
  { total: 2500, remaining: 2499, reset: 1485859856 },
  { total: 2500, remaining: 2499, reset: 1485859856 },
  { total: 2500, remaining: 2499, reset: 1485859856 },
  { total: 2500, remaining: 2499, reset: 1485859856 },
  { total: 2500, remaining: 2498, reset: 1485859856 },
  { total: 2500, remaining: 2498, reset: 1485859856 } ]

Probably due to n value not getting updated. Sent a pr to try fixing this issue. Comments are appreciated.