code: func (ptree *ptree) Dispose() {
  	if atomic.LoadUint64(&ptree.disposed) == 1 {
  		return
  	}
  	ptree.actions.Dispose()
  	atomic.StoreUint64(&ptree.disposed, 1)
  	close(ptree.disposeChannel)
  }
docs: // Dispose will clean up any resources used by this tree.  This
  // must be called to prevent a memory leak.