def sd_journal_send(**kwargs):
    """
    Send a message to the journald log.

    @param kwargs: Mapping between field names to values, both as bytes.

    @raise IOError: If the operation failed.
    """
    # The function uses printf formatting, so we need to quote
    # percentages.
    fields = [
        _ffi.new(
            "char[]", key.encode("ascii") + b'=' + value.replace(b"%", b"%%"))
        for key, value in kwargs.items()]
    fields.append(_ffi.NULL)
    result = _journald.sd_journal_send(*fields)
    if result != 0:
        raise IOError(-result, strerror(-result))
Send a message to the journald log.

    @param kwargs: Mapping between field names to values, both as bytes.

    @raise IOError: If the operation failed.