question about waterfall with setTimeout or process.nextTick

[enginespot]

code like the follows:
for the second function , it will be called after 1 second , so my question is how to pass the data 'three' to the next function

async.waterfall([
    function(callback){
        callback(null, 'one', 'two');
    },
    function(arg1, arg2, callback){
        setTimeout(callback.bind(null,"three"),1000);
//        callback(null, 'three');
    },
    function(arg1, callback){
        // arg1 now equals 'three'
        callback(null, 'done');
    }
], function (err, result) {
   // result now equals 'done'    
});

[enginespot]

I find the requirement of mine is very familiar with the 'compose' api, so I change the waterfall2 as follows

async.waterfall2 = function(tasks, callback) {
  var _this = this;
  async.reduce(tasks, [], function(newargs, fn, cb) {
    fn.apply(_this, newargs.concat([
      function() {
        var err, nextargs;
        err = arguments[0];
        nextargs = Array.prototype.slice.call(arguments, 1);
        cb(err, nextargs);
      }
    ]));
  }, function(err, results) {
    callback.apply(_this, [err].concat(results));
  });
};