async fn lookup_chat_or_create_adhoc_group(
    context: &Context,
    mime_parser: &MimeMessage,
    parent: &Option<Message>,
    to_ids: &[ContactId],
    from_id: ContactId,
    allow_creation: bool,
    create_blocked: Blocked,
    is_partial_download: bool
) -> Result<Option<(ChatId, Blocked)>>