presto-main/src/main/java/io/prestosql/sql/planner/plan/AssignUniqueId.java/AssignUniqueId/AssignUniqueId
class AssignUniqueId:    @JsonCreator
    public AssignUniqueId(
            @JsonProperty("id") PlanNodeId id,
            @JsonProperty("source") PlanNode source,
            @JsonProperty("idColumn") Symbol unique)
    {
        super(id);
        this.source = requireNonNull(source, "source is null");
        this.idColumn = requireNonNull(unique, "idColumn is null");
    }