how to get hot water when brewing tea fresh outdoors?

I keep seeing pictures here of people drinking in parks or on hikes, and I've seen the loveliest travel tea sets (noooo, that's not my motivation to drink outside at all....).

But I'm wondering how to get hot water when you're out in the outback? Other than pre-brewing the tea and putting it into a flask (fine but not optimal) or having hot water in a flask and just accepting that it's not going to be that hot anymore upon arrival (fine for teas to be brewed at a lower temperature I suppose?), or actually making a fire and bringing a pot and everything (often not possible), I have no ideas.