Binary upload header 'Content-Disposition' is not encoded properly

The header parameter filename in multipartUpload is properly encoded:

background_downloader/lib/src/desktop/upload_isolate.dart

Lines 134 to 137 in 0fd4756

    
           contentDispositionStrings.add( 
        
             'Content-Disposition: form-data; name="${browserEncode(fileField)}"; ' 
        
             'filename="${browserEncode(p.basename(file.path))}"$lineFeed', 
        
           );

However, in binaryUpload it is not:

background_downloader/lib/src/desktop/upload_isolate.dart

Lines 52 to 53 in 0fd4756

    
           request.headers['Content-Disposition'] = 
        
               'attachment; filename="${task.filename}"';

Which leads to "Invalid HTTP header" errors when trying to upload files with non-latin characters.

I didn't notice that browserEncode does not actually perform encoding but only replaces some characters. I'm guessing we would need to use Uri.encodeComponent.

Included in V8.5.6

	contentDispositionStrings.add(
	'Content-Disposition: form-data; name="${browserEncode(fileField)}"; '
	'filename="${browserEncode(p.basename(file.path))}"$lineFeed',
	);

	request.headers['Content-Disposition'] =
	'attachment; filename="${task.filename}"';