code: boolean tryToRetire(Node<K, V> node, WeightedValue<V> expect) {
          if (expect.isAlive()) {
              final WeightedValue<V> retired = new WeightedValue<V>(expect.value, -expect.weight);
              return node.compareAndSet(expect, retired);
          }
          return false;
      }
docs: Attempts to transition the node from the <tt>alive</tt> state to the
  <tt>retired</tt> state.
  
  @param node the entry in the page replacement policy
  @param expect the expected weighted value
  @return if successful