code: void afterRead(Node<K, V> node) {
          final int bufferIndex = readBufferIndex();
          final long writeCount = recordRead(bufferIndex, node);
          drainOnReadIfNeeded(bufferIndex, writeCount);
          notifyListener();
      }
docs: Performs the post-processing work required after a read.
  
  @param node the entry in the page replacement policy