Support first contentful paint event in document load plugin

[8tme]

What happened?

What happened?

What happened?

Steps to Reproduce

use like this in my react app

  registerInstrumentations({
    instrumentations: [
      new DocumentLoadInstrumentation({}),
    ],
  })

Expected Result

document load span whith 11 events

Actual Result

document load span whith 9 events

Additional Details

After a meticulous investigation, I have identified several potential causes that lead to this issue. when executing

if (!this.getConfig().ignoreNetworkEvents) {
        addSpanNetworkEvents(span, resource);
}

otperformance is always an empty array. I realize that this can only be achieved through asynchronous retrieval.

the code is located here
https://github.com/open-telemetry/opentelemetry-js-contrib/blob/1eb77007669bae87fe5664d68ba6533b95275d52/plugins/web/opentelemetry-instrumentation-document-load/src/instrumentation.ts#L208

by the way, why wasn't there a distinction between node and browser when introducing the platform in opentelemetry-core?

[pichlermarc]

cc @pkanal @martinkuba (component owners)

[dyladan]

This instrumentation is not indicative of the direction the client/browser SIG is planning to go. It will be rewritten when there is a good specification for browser events. This work is ongoing but I don't think this instrumentation is likely to get any real enhancements before then.

[8tme]

This instrumentation is not indicative of the direction the client/browser SIG is planning to go. It will be rewritten when there is a good specification for browser events. This work is ongoing but I don't think this instrumentation is likely to get any real enhancements before then.

Why can't we set up an asynchronous task (e.g., with a 3-second delay) to collect the network spans, even if we can't guarantee that FCP has occurred by then? For example, we could set a timeout of 3 seconds, and if after that time we still haven't collected the data, it would indicate an inherent issue with the page itself.

[8tme]

be like this
const GET_FCP_DELAY = 3000; if (!this.getConfig().ignoreNetworkEvents) { setTimeout(() => addSpanNetworkEvents(span, resource), GET_FCP_DELAY) }