これまだ使えないと思ってたけど、experimental.requestInsightsを有効にしたら使えた
データフェッチのウォーターフォールが可視化されるの本当に素晴らしすぎる
Next.js Request Insights devtool
TLDR: Allows you to quickly inspect where time was spent for individual requests
Details:
We've been exploring adding a new tab to the Next.js devtools that visualizes the tracing data that is already collected during development.
When a request comes in to the server Next.js already instruments it end-to-end for e.g. OpenTelemetry.
Sometimes you just want to inspect where time was spent for a particular request and setting up a telemetry report is too much work, especially in development. That's where this tool fits in to get a quick overview of where time was spent.
There's some more work to do to cover some missing spans, for example the route matching.
Also exploring some design changes.