def get_dir_from_zipfile(zip_file, fallback=None):
    """Return the name of the root folder in a zip file.

    :param zip_file: a :class:`zipfile.ZipFile` instance.
    :param fallback: if `None`, the name of the zip file is used. This is
        returned if the zip file contains more than one top-level directory,
        or none at all.
    """
    fallback = fallback or zip_file.filename
    directories = [name for name in zip_file.namelist() if name.endswith("/")
                   and len(PurePath(name).parts) == 1]
    return fallback if len(directories) > 1 else directories[0]
async def echo_client_streams(reader, writer):
    sock = writer.get_extra_info('socket')
    try:
        sock.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)
    except (OSError, NameError):
        pass
    if PRINT:
        print('Connection from', sock.getpeername())
    while True:
        data = await reader.read(1000000)
        if not data:
            break
        writer.write(data)
    if PRINT:
        print('Connection closed')
    writer.close()