Misc/NEWS.d/next/Library/2019-05-28-01-06-44.bpo-37054.sLULGQ.rst

Fix destructor :class:`_pyio.BytesIO` and :class:`_pyio.TextIOWrapper`:
initialize their ``_buffer`` attribute as soon as possible (in the class
body), because it's used by ``__del__()`` which calls ``close()``.