message: parallelize unnest
diff: @@ -106,6 +106,7 @@ bool Pipeline::ScheduleOperator(PhysicalOperator *op) {
  // CREATE TABLE AS
  return ScheduleOperator(op->children[0].get());
  }
  + case PhysicalOperatorType::UNNEST:
  case PhysicalOperatorType::FILTER:
  case PhysicalOperatorType::PROJECTION:
  case PhysicalOperatorType::HASH_JOIN:
  @@ -178,6 +179,7 @@ void Pipeline::Schedule() {
  break;
  }
  case PhysicalOperatorType::CREATE:
  + case PhysicalOperatorType::UNNEST:
  case PhysicalOperatorType::ORDER_BY:
  case PhysicalOperatorType::RESERVOIR_SAMPLE:
  case PhysicalOperatorType::PERFECT_HASH_GROUP_BY: {
  