useRouterState - documentation?

Hi, I saw this in the

Kitchen Sink React Query File Based

Kitchen Sink React Query File Based

example in __root.tsx:

function RouterSpinner() {
  const isLoading = useRouterState({ select: (s) => s.status === 'pending' })
  return <Spinner show={isLoading} />
}

function RouterSpinner() {
  const isLoading = useRouterState({ select: (s) => s.status === 'pending' })
  return <Spinner show={isLoading} />
}

Is there any documentation for

useRouterState()

useRouterState()

. I like the idea of a global spinner, but I wasn't quite sure how this all worked and so far couldn't find any documentation for this hook.