\n"))
    ''

    >>> read_stringnl(io.BytesIO(b'"abcd"'))
    Traceback (most recent call last):
    ...
    ValueError: no newline found when trying to read stringnl

    Embedded escapes are undone in the result.
    >>> read_stringnl(io.BytesIO(br"'a\n\\b\x00c\td'" + b"\n'e'"))
    'a\n\\b\x00c\td'
    ó