presto-main/src/main/java/io/prestosql/sql/planner/SubqueryPlanner.java/SubqueryPlanner/appendScalarSubqueryCorrelatedJoins
class SubqueryPlanner:    private PlanBuilder appendScalarSubqueryCorrelatedJoins(PlanBuilder builder, Set<SubqueryExpression> scalarSubqueries, boolean correlationAllowed)
    {
        for (SubqueryExpression scalarSubquery : scalarSubqueries) {
            builder = appendScalarSubqueryApplyNode(builder, scalarSubquery, correlationAllowed);
        }
        return builder;
    }