Astarte.Device.Handler.init_state

You're seeing just the callback init_state, go back to Astarte.Device.Handler module for more information.
Link to this callback

init_state(args)

Specs

init_state(args :: term()) ::
  {:ok, state :: term()} | {:error, reason :: term()}

Initialize the state that will be passed as second argument to handle_message/2.

If this function returns {:error, reason}, the handler process is stopped with reason reason.