private int keyAtGivenLocksAndBufferAcquired(ByteBuffer pageBuffer,
                                                 int slotIndex) {
      final int keyOffsetInNode = indexToOffset(slotIndex) + KEY_OFFSET;
      return getIntGivenLocksAndBufferAcquired(pageBuffer, keyOffsetInNode);
    }
private int keyAtGivenLocksAndBufferAcquired(ByteBuffer pageBuffer,
                                                 int slotIndex)