Vue.js: What is the difference between useRequestEvent and useRequestHeaders in Nuxt 3?

1// server/api/my-api.ts
2export default defineEventHandler((event) => {
3    const headers = getRequestHeaders(event)
4    const query = getQuery(event)
5    return { headers, query }
6})

1<script setup>
2// Only on server
3const headers = useRequestHeaders()
4const cookie = headers.cookie
5</script>