code: function(bs, done) {
          utils.getPorts(bs.options, function(err, port) {
              if (err) {
                  return utils.fail(true, err, bs.cb);
              }
              bs.debug("Found a free port: {magenta:%s", port);
              done(null, {
                  options: {
                      port: port
                  }
              });
          });
      }
docs: BrowserSync needs at least 1 free port.
  It will check the one provided in config
  and keep incrementing until an available one is found.
  @param {BrowserSync} bs
  @param {Function} done