next.js/test/e2e/app-dir/segment-cache/prefetch-layout-sharing/app/shared-layout/layout.tsx

import { cookies } from 'next/headers'
import { Suspense } from 'react'
import { cachedDelay, DebugRenderKind, uncachedIO } from '../shared'
import { connection } from 'next/server'

export default async function Layout({ children }) {
  return (
    <main>
      <div>
        <h2>Shared layout</h2>
        <DebugRenderKind />
        <p id="shared-layout-description">
          This shared layout uses cookies and some uncached IO, so parts of it
          should be runtime-prefetchable.
        </p>
        <Suspense fallback={<div style={{ color: 'grey' }}>Loading 1...</div>}>
          <RuntimePrefetchable />
        </Suspense>
      </div>
      <hr />
      {children}
    </main>
  )
}

async function RuntimePrefetchable() {
  const cookieStore = await cookies()
  const cookieValue = cookieStore.get('testCookie')?.value ?? null
  await cachedDelay([__filename, cookieValue])
  return (
    <div style={{ border: '1px solid blue', padding: '1em' }}>
      <div id="cookie-value-layout">{`Cookie from layout: ${cookieValue}`}</div>
      <Suspense fallback={<div style={{ color: 'grey' }}>Loading 2...</div>}>
        <Dynamic />
      </Suspense>
    </div>
  )
}

async function Dynamic() {
  await uncachedIO()
  await connection()
  return (
    <div style={{ border: '1px solid tomato', padding: '1em' }}>
      <div id="dynamic-content-layout">Dynamic content from layout</div>
    </div>
  )
}