We might learn from the gaming dev community, where stateful servers are quite common. It's interesting to see that for example agar.io (web-based realtime game

We might learn from the gaming dev community, where stateful servers are quite common. It's interesting to see that for example agar.io (web-based realtime game) started in C++ and moved to Erlang, both of which uncommon choices for web software, though the latter seems to be rising, particularly in the form of Elixir.