As a convenience it would be useful if async.open_connection() and open_unix_connection() would return a context manager that closes the writer on exit:

    with await open_unix_connection(...) as (reader, writer):
        ...

This could be achieved by using a custom sub-class of tuple:

    class _ConnectionContext(tuple):
        def __enter__(self):
            return self
        def __exit__(self, *args):
            self[1].close()

I can submit a PR if wanted.