code: func (h *Handle) Release() {
  	nPtr := atomic.LoadPointer(&h.n)
  	if nPtr != nil && atomic.CompareAndSwapPointer(&h.n, nPtr, nil) {
  		n := (*Node)(nPtr)
  		n.unrefLocked()
  	}
  }
docs: // Release releases this 'cache handle'.
  // It is safe to call release multiple times.