This is very confusing as seen in #12974 or #12906. My suggestion would be "legacy."
function () {
              finishWorkerTask(task);
              if (start) {
                info(
                  `page=${pageIndex + 1} - getTextContent: time=` +
                    `${Date.now() - start}ms`
                );
              }
              sink.close();
            },
            function (reason) {
              finishWorkerTask(task);
              if (task.terminated) {
                return; 
              }
              sink.error(reason);
              
              
            }
          );
      });
    });
    handler.on("FontFallback", function (data) {
      return pdfManager.fontFallback(data.id, handler);
    });
    handler.on("Cleanup", function wphCleanup(data) {
      return pdfManager.cleanup( true);
    });
    handler.on("Terminate", function wphTerminate(data) {
      terminated = true;