"""A utility class to write to and read from a non-blocking file or socket.
We support a non-blocking ``write()`` and a family of ``read_*()``
- methods. When the operation completes, the `.Future` will resolve
+ methods. When the operation completes, the ``Awaitable`` will resolve
with the data read (or ``None`` for ``write()``). All outstanding
- ``Futures`` will resolve with a `StreamClosedError` when the
+ ``Awaitables`` will resolve with a `StreamClosedError` when the
stream is closed; `.BaseIOStream.set_close_callback` can also be used
to be notified of a closed stream.