code: func (d *DiskStorer) StartCleaner() {
  	if d.maxAge == 0 || d.cleanInterval == 0 {
  		panic("both max age and clean interval must be set to non-zero")
  	}
  
  	// init quit chan
  	d.quit = make(chan struct{})
  
  	d.wg.Add(1)
  
  	// Start the cleaner infinite loop go routine.
  	// StopCleaner() can be used to kill this go routine.
  	go d.cleanerLoop()
  }
docs: // StartCleaner starts the disk session cleaner go routine. This go routine
  // will delete expired disk sessions on the cleanInterval interval.