title: Call variable number of functions in parallel?
body: <p>Using async.parallel or custom control flow,</p>
  
  <pre><code>arr = [1, 2, 3, 4, 5, 3, 2, 3, 4, 5] //arr could be any length
  
  get_something = function(num, cb){
    async_io(num, function (err, results){
          cb()
    });
  
  } 
  </code></pre>
  
  <p>I want to run get_something() on each member of the array in "parallel". When they're all finished I'd like the callback to get called with the results.  </p>