presto-main/src/main/java/io/prestosql/operator/NestedLoopBuildOperator.java/NestedLoopBuildOperator/finish
class NestedLoopBuildOperator:    @Override
    public void finish()
    {
        if (probeDoneWithPages.isPresent()) {
            return;
        }

        // nestedLoopJoinPagesBuilder and the built NestedLoopJoinPages will mostly share the same objects.
        // Extra allocation is minimal during build call. As a result, memory accounting is not updated here.
        probeDoneWithPages = Optional.of(nestedLoopJoinBridge.setPages(nestedLoopJoinPagesBuilder.build()));
    }