Route param
The [id] segment is: hello
Typed with PageProps<'/features/routing/[id]'>,
so params.id is a checked
string from the generated route union.
params is awaitable too:
const { id } = await params works, same value.
Throwing wins over rendering: /features/routing/missing
throws notFound() and renders the nearest
not-found boundary at 404. See the
Boundaries demo for
forbidden() and
unauthorized().