[@opentelemetry/instrumentation-undici] make http.response.status_code available for use in hooks

[cpatti97100]

Is your feature request related to a problem? Please describe

Good morning all, I tried to use the 2 exposed hooks requestHook and startSpanHook from @opentelemetry/instrumentation-undici in order to access http.response.status_code from the span and copy its value into http.status_code for compatibility with our systems. From my understanding, this hooks run at a point in time before the monitored request actually concludes, so there is no way currently to achieve this.

Describe the solution you'd like to see

A hook that allows you to modify the span in terms of attributes after the request succeeded or failed.

Describe alternatives you've considered

Additional context

new UndiciInstrumentation({
        requestHook: (span, request) => {
          span.setAttribute(
            'http.host',
            span.attributes['server.address'] +
              ':' +
              span.attributes['server.port']
          )
          span.setAttribute(
            'http.method',
            span.attributes['http.request.method']
          )
          span.setAttribute(
            'http.target',
            span.attributes['url.path'] + span.attributes['url.query']
          )
          span.setAttribute('http.url', span.attributes['url.full'])
          
          // http.response.status_code does not exist yet
          span.setAttribute(
            'http.status_code',
            parseInt(span.attributes['http.response.status_code'])
          )
        },
      })