presto-main/src/main/java/io/prestosql/execution/QueryManagerConfig.java/QueryManagerConfig/setStageCountWarningThreshold
class QueryManagerConfig:    @Config("query.stage-count-warning-threshold")
    @ConfigDescription("Emit a warning when stage count exceeds this threshold")
    public QueryManagerConfig setStageCountWarningThreshold(int stageCountWarningThreshold)
    {
        this.stageCountWarningThreshold = stageCountWarningThreshold;
        return this;
    }