anchor.diff:  -define(DEFAULT_ENDPOINTS, [{http, "localhost", 9090, []}]).
   
   -record(state, {protocol :: grpc | http_protobuf | http_json,
  -                channel_pid :: pid(),
  +                channel_pid :: pid() | undefined,
                   endpoints :: list()}).
   
   init(Opts) ->
  
positive.code: to_attributes([_ | Rest], Acc) ->
      to_attributes(Rest, Acc).
  
  to_status(#status{code=Code,
                    message=Message}) ->
      #{code => Code,
  
negative.code:       trace_id                 => <<TraceId:128>>,
        span_id                  => <<SpanId:64>>,
        parent_span_id           => ParentSpanId,
        trace_state              => to_tracestate_string(TraceState),
        kind                     => Kind,
        start_time_unix_nano     => to_unixnano(StartTime),
        end_time_unix_nano       => to_unixnano(EndTime),
        attributes               => to_attributes(Attributes),
        dropped_attributes_count => 0,
        events                   => to_events(TimedEvents),
  