code: func newServingQueue(suspendBias int64) *servingQueue {
  	sq := &servingQueue{
  		queue:        prque.New(nil),
  		suspendBias:  suspendBias,
  		tokenCh:      make(chan runToken),
  		queueAddCh:   make(chan *servingTask, 100),
  		queueBestCh:  make(chan *servingTask),
  		stopThreadCh: make(chan struct{}),
  		quit:         make(chan struct{}),
  		setThreadsCh: make(chan int, 10),
  	}
  	sq.wg.Add(2)
  	go sq.queueLoop()
  	go sq.threadCountLoop()
  	return sq
  }
docs: // newServingQueue returns a new servingQueue