presto-main/src/main/java/io/prestosql/operator/SetBuilderOperator.java/SetBuilderOperatorFactory/SetBuilderOperatorFactory
class SetBuilderOperatorFactory:        public SetBuilderOperatorFactory(
                int operatorId,
                PlanNodeId planNodeId,
                Type type,
                int setChannel,
                Optional<Integer> hashChannel,
                int expectedPositions,
                JoinCompiler joinCompiler)
        {
            this.operatorId = operatorId;
            this.planNodeId = requireNonNull(planNodeId, "planNodeId is null");
            Preconditions.checkArgument(setChannel >= 0, "setChannel is negative");
            this.setProvider = new SetSupplier(requireNonNull(type, "type is null"));
            this.setChannel = setChannel;
            this.hashChannel = requireNonNull(hashChannel, "hashChannel is null");
            this.expectedPositions = expectedPositions;
            this.joinCompiler = requireNonNull(joinCompiler, "joinCompiler is null");
        }