One niche feature of Erlang that I love is live module upgrades, particularly via gen_server's code_change/3 callback. It's a neat little trick that seems to be rarely used in practice, but every single time I've used it I just loved how everything simply clicked together, providing zero disruption with nearly minimal effort (for simple state upgrades or downgrades).

I wonder if it's supported with Gleam and/or gleam_otp? Don't see it in the docs.