Attempting a Google Drive partial Download (Flutter) throws a header error - flutter

Question

Here's my issue :
I am creating a small application based on audio files stored on Google Drive, in Flutter.
I am using the drive api to make my requests, with these scopes in my google sign in :
GoogleSignIn _googleSignIn = GoogleSignIn(
scopes: [
'email',
'https://www.googleapis.com/auth/userinfo.profile',
'https://www.googleapis.com/auth/contacts.readonly',
'https://www.googleapis.com/auth/drive',
'https://www.googleapis.com/auth/docs',
'https://www.googleapis.com/auth/drive.appdata',
],
);
I have an auth element and handle signing in and out. Until then, no issues.
I can also request my files with an implementation looking like this :
var api = widget.api.getAPI();
var files = await api.files.list($fields: '*');
This works perfectly, and so does :
var api = widget.api.getAPI();
var files = await api.files.get("myFileId"); (//does get a file instance)
But since I'd like to retrieve some of the Metadata included in my audio files, and since the drive API doesn't natively support extracting audio metadata and sending it as a google metadata, I thought I'd extract it with a partial download on the file itself.
Here's the catch : I can't seem to get the partial download to work.
Based on the doc, I thought the implementation would look something like this :
import 'package:googleapis/drive/v3.dart' as ga;
(...)
try {
var partiallyDownloadedFile = await api.files.get(
"myFileIdHere",
downloadOptions: ga.PartialDownloadOptions(ga.ByteRange(0, 10))); //should get a ga.Media instance
print("partial download succeeded");
print(partiallyDownloadedFile);
//(...do stuff...)
return;
} catch (err) {
print('Error occured : ');
print(err);
return;
}
But this always throws this error :
ApiRequestError(message: Attempting partial download but got invalid
'Content-Range' header (was: null, expected: bytes 0-10/).)
I tried using it on Wav files, but also MP4 files. The error is always the same, which leads me to believe it's my implementation that's somehow wrong, but I'm not sure what I'm supposed to do to fix it. Is it my request missing the header ? The response not including it ?
While very clear, that error doesn't help me troubleshoot my issue at all. I can't seem to find any documentation on how to conduct a partial media request. I haven't found any example projects to compare it with.
PartialDownloadOptions does not have much documentation.
I could handmake a partial request through the download links (which is how I can read the music to begin with) but the drive API supposedly allows this. Could anyone familiar with Flutter/the google APIs help me correct my implementation?

Answer 1

EDIT : This was due to an error within the commons library in the Dart google APIs, and was (at the very least superficially) fixed thanks to Kevmoo's efforts : https://github.com/google/googleapis.dart/issues/462
It was a Content-Range error happening due to browser specifications with access-control-expose-header compared to iOS/Android-type requests that typically expose every header.