presto-main/src/main/java/io/prestosql/operator/HashBuilderOperator.java/HashBuilderOperator/isFinished
class HashBuilderOperator:    @Override
    public boolean isFinished()
    {
        if (lookupSourceFactoryDestroyed.isDone()) {
            // Finish early when the probe side is empty
            close();
            return true;
        }

        return state == State.CLOSED;
    }