GenStage used :error_logger so it looks like GenServer and other behaviours written in Erlang/OTP. Unless you are writing a low-level abstraction that should behave like a GenServer, then always use Logger. Even :error_logger itself is deprecated and we will have to update GenStage source at some point.
Ok, thank you @josevalim for the clarification. If I were to write a low-level abstraction, what should I use then. Have you already decided what you will use for GenStage? Maybe the “new” Erlang :logger?