anchor.diff:  to_instrumentation_library(_) ->
       undefined.
   
  +%% TODO: figure out why this type spec fails
  +%% -spec to_proto(#span{}) -> opentelemetry_exporter_trace_service_pb:span().
  +
   to_proto(#span{trace_id=TraceId,
                  span_id=SpanId,
                  tracestate=TraceState,
  
positive.code:                 tracestate=TraceState} | Rest], Acc) ->
      to_links(Rest, [#{trace_id => <<TraceId:128>>,
                        span_id => <<SpanId:64>>,
                        tracestate => TraceState,
                        attributes => to_attributes(Attributes),
                        dropped_attributes_count => 0} | Acc]).
  
  
negative.code: to_status(_) ->
      #{}.
  
  -spec to_events([opentelemetry:events()]) -> [opentelemetry_exporter_trace_service_pb:event()].
  to_events(Events) ->
      to_events(Events, []).
  
  