Next.js automatically instruments several spans for you to provide useful insights into your application's performance.
Attributes on spans follow OpenTelemetry semantic conventions. We also add some custom attributes under the next namespace:
next.span_name - duplicates span name
next.span_type - each span type has a unique identifier
next.route - The route pattern of the request (e.g., /[param]/user).
next.page
This is an internal value used by an app router.
You can think about it as a route to a special file (like page.ts, layout.ts, loading.ts and others)
It can be used as a unique identifier only when paired with next.route because /layout can be used to identify both /(groupA)/layout.ts and /(groupB)/layout.ts
[http.method] [next.route]
next.span_type: BaseServer.handleRequest