code: final void addPointer(int keyPos, int keySize, int valuePos, int valueSize) {
      assert keyPos + keySize == valuePos;
      int start = memoryBuffer.limit() - POINTER_SIZE_BYTES;
      memoryBuffer.putInt(start, keyPos);
      memoryBuffer.putInt(start + 4, valuePos);
      memoryBuffer.putInt(start + 8, valueSize);
      memoryBuffer.limit(start);
      valuesHeld++;
    }
docs: Add a pointer to the key value pair with the provided parameters.