code: func (m *Meter) FinishTransfer(name string) {
  	if m == nil {
  		return
  	}
  
  	defer m.update(false)
  	atomic.AddInt64(&m.finishedFiles, 1)
  	m.fileIndexMutex.Lock()
  	delete(m.fileIndex, name)
  	m.fileIndexMutex.Unlock()
  }
docs: // FinishTransfer increments the finished transfer count