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_status(_) ->
      #{}.
  
  to_events(Events) ->
      to_events(Events, []).
  
  
negative.code: to_unixnano(Timestamp) ->
      opentelemetry:timestamp_to_nano(Timestamp).
  
  -spec to_attributes(opentelemetry:attributes()) -> [opentelemetry_exporter_trace_service_pb:attribute_key_value()].
  to_attributes(Attributes) ->
      to_attributes(Attributes, []).
  
  