private void handleClick(NPC npc, Player clicker) {
        if (npc.hasTrait(ClickableTrait.class)) {
            if (processMetadata(clicker)) {
                return;
            }
            npc.getTrait(ClickableTrait.class).onClick(clicker);
        }
    }
Implementation of {@link NpcFactory} using Citizens.
helper/src/main/java/me/lucko/helper/npc/CitizensNpcFactory.java