This is very confusing as seen in #12974 or #12906. My suggestion would be "legacy."
var task = new WorkerTask(`GetOperatorList: page ${pageIndex}`);
        startWorkerTask(task);
        
        const start = verbosity >= VerbosityLevel.INFOS ? Date.now() : 0;
        
        page
          .getOperatorList({
            handler,
            sink,
            task,
            intent: data.intent,
            renderInteractiveForms: data.renderInteractiveForms,
            annotationStorage: data.annotationStorage,
          })
          .then(
            function (operatorListInfo) {
              finishWorkerTask(task);
              if (start) {
                info(
                  `page=${pageIndex + 1} - getOperatorList: time=` +
                    `${Date.now() - start}ms, len=${operatorListInfo.length}`
                );
              }
              sink.close();
            },
            function (reason) {
              finishWorkerTask(task);
              if (task.terminated) {
                return; 
              }