code: func (q *BaseQueue) Processor() Processor {
  	q.pmu.RLock()
  	defer q.pmu.RUnlock()
  
  	if q.processor == nil {
  		return FIFO
  	}
  
  	return q.processor
  }
docs: // Source implements the Source method on the Queue interface. It functions by
  // requesting a read-level lock from the guarding mutex and returning that value
  // once obtained. If no processor is set, the the default FIFO implementation is
  // returned.