Combination of QTextStream and QFile doesn't save the file contents

• With https://codereview.qt-project.org/#/c/164371/ applied:
• Launch examples/mainwindows/application/application.py
• Write something in the textarea
• Invoke save action, choose a name, and save the file
• Try to open with another text editor the file, and see that it is empty.

Opening an existing file with existing content (using the example), and saving it, will also clear the content of the file.

I've seen another example which used QFile.save() explicitly, and it worked properly.

But it seems that a combination of QFile and QTextStream, does not work.