code: function after(count, callback) {
      var countdown = count;
  
      return function shim(err) {
          if (typeof callback !== 'function') return;
  
          if (err) {
              callback(err);
              callback = null;
              return;
          }
  
          if (--countdown === 0) {
              callback();
              callback = null;
          }
      };
  }
docs: IGNORE THIS! It's a little utility function that invokes a callback after a specified number of invocations of its shim.