How can I add http headers to vtkHttpDataSetReader ?

I am trying to upload a file in vtk.js .gz format from a server that needs authentication.
I need add Authorization header to vtkHttpDataSetReader.
How can I add headers to vtkHttpDataSetReader ?

const reader = vtkHttpDataSetReader.newInstance({ fetchGzip: true });
reader.setUrl("", {loadData: true, headers:{"Authorization": "ZBXHSsxcss...."} }).then(() => {...});

This code does not work the header is not added.

The options are not kept for the actual requests. But the code can be updated to properly handle it.
Contribution are welcome.