row.meta.cursor in step always same value when parsing in worker mode

Not sure if this is a bug or simply a limitation of parsing in worker mode, but when I parse a (local) file in worker mode, the row.meta.cursor always points to the end of the file:

Papa.parse(file, {
  header: true,
  worker: true, // << worker is true
  step: (row, parser) => {
    console.log(row.meta.cursor, file.size);
    // => logs "677403 677403" 8973 times
  },
});

Papa.parse(file, {
  header: true,
  worker: false, // << worker is false
  step: (row, parser) => {
    console.log(row.meta.cursor, file.size);
    // => logs increasisng number upto filesize as expected
  },
});

Is there any way to get the cursor (or anything else that can be used as a progress-indicator) when parsing in worker mode?