The raw message looks like this:
@badges=staff/1,turbo/1;color=#00CDFF;display-name=3ventic;emotes=25:0-4;message-id=90;thread-id=17089325_76480729;turbo=1;user-id=17089325;user-type=staff :3ventic!3ventic@3ventic.tmi.twitch.tv WHISPER notventic :Kappa
Try using onUnknown(String line) and parsing it yourself, otherwise you’ll need someone who knows pircbot. It might also be worth looking into pircbotx, which supports tags as well, as far as I know.