Redis potential bug replication

redis-test.js

var redis = require('redis');
var options = {
  host: '127.0.0.1',
  port: '6379'
};

var publisher = redis.createClient(options);
var subscriber = redis.createClient(options);

function sub(message) {
  subscriber.on('subscribe', function () {
    console.log('publishing');
    publisher.publish('/foo', message);
  });
  subscriber.on('message', function (channel, message) {
    console.log('message: ' + message);
  });
  subscriber.on('unsubscribe', function (channel, count) {
    console.log('unsub: ' + count);
  });
  subscriber.subscribe('/foo');
}

sub('hello');

setTimeout(function () {
  subscriber.unsubscribe();
  setTimeout(function () {
    sub('world');
  }, 4000);
}, 4000);