trio.wrap_file() undocumented behavior wrt to sync file object

Hello,

Looking at https://trio.readthedocs.io/en/stable/reference-io.html#trio.wrap_file, it is not clear to me if:

• Closing the returned async file object will also close the sync file object that I passed in
• Whether this will happen automatically when the async file object is garbage collected
• If I can continue to use the sync file object at the same time.

It'd be great if that could be clarified!