code: private void bufferRows2() throws IOException {
  		BinaryRow copy = key2.copy();
  		buffer2.reset();
  		do {
  			buffer2.add(row2);
  		} while (nextRow2() && keyComparator.compare(key2, copy) == 0);
  		buffer2.complete();
  	}
docs: Buffer rows from iterator2 with same key.