Function customFetchData

packages/query-core/src/__tests__/hydration.test.tsx:698–709

()

    let resolvePromise: (value: unknown) => void = () => undefined

    const customFetchData = () => {
      const promise = new Promise((resolve) => {
        resolvePromise = resolve
      })
      // Resolve the promise in initial fetch
      // because we are awaiting the query first time
      if (isInitialFetch) {
        resolvePromise('string')
      }
      isInitialFetch = false
      return promise
    }

    await queryClient.prefetchQuery({
      queryKey: key,