anchor.diff:  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   
   %% @private
  --spec init([term()]) -> {ok, at_rest, map()} | {stop, gun_open_timeout} | {stop, gun_open_failed}.
  +-spec init([term()]) -> {ok, at_rest, map()}
  +                        | {stop, gun_open_timeout} | {stop, gun_open_failed}.
   init([Host, Port, Type, Opts]) ->
       GunType = case Type of
                     http -> tcp;
  
positive.code: %% @private
  check_uri([$/ | _]) -> ok;
  check_uri(_) -> throw(missing_slash_uri).
  
negative.code:         #{
              transport_opts => [],
              timeout => pos_integer() | infinity }.
  %% transport_opts are passed to Ranch's TCP transport, which is -itself-
  %% a thin layer over gen_tcp. <br/>
  %% timeout is passed to gun:await_up. Default if not specified is 5000 ms.
  
  %% @doc Starts the application and all the ones it depends on.
  