WebExtension webRequest.onAuthRequired seems not working

Hi,

I am trying the webRequest.onAuthRequired API on Safari WebExtension. From MDN document: https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API/webRequest/onAuthRequired, Safari WebExtension doesn't support extraInfoSpec

After inspecting the background, the webRequest.onAuthRequired callback is triggered, but in the callback I return the credentials directly

chrome.webRequest.onAuthRequired.addListener(
  function(details) {
    return {
      authCredentials: {
        username: 'username',
        password: 'password'
      }
    }
  },
  { urls: ['<all_urls>'] }
);

It still doesn't work, Any ideas to resolve this?

Thanks a lot!