code: function nextTick() {
          /*jshint validthis:true*/
          var self = this;
  
          // never resolve when tasks are finished
          if (self.nextTask < self.tasks.length) {
              // if tasks are still queueing
              // increment nextTask
              if (++self.nextTask !== self.tasks.length) return self;
          }
  
          // check callbacks if all tasks are finished
          resolveCallback.call(self);
          return self;
      }
docs: @private
  @name nextTick
  Advance to next tick in the queue
  For AsyncQueue#reject or AsyncQueue#resolve
  
  @param {String} handle
  @param {Object} data