code: private void bufferRows1() throws IOException {
  		BinaryRow copy = key1.copy();
  		buffer1.reset();
  		do {
  			buffer1.add(row1);
  		} while (nextRow1() && keyComparator.compare(key1, copy) == 0);
  		buffer1.complete();
  	}
docs: Buffer rows from iterator1 with same key.