Add example defer to demo

[eddeee888]

This is an example of how Yoga supports @defer:

• Book:2 is a very slow book
• So we wrap @defer when resolving books. It is ONLY slow when it's loading 2. Here's the query:

  query BookDetails($bookId: ID!) {
    book(id: $bookId) {
      ... on BookResultOk {
        result {
          id
          isbn
          ... on Book @defer { # since we are loading `Book:3`, the previous book will be slow, making `Previous` link slow to appear
            previousBookInSeries {
              id
            }
          }
          ... on Book @defer {
            nextBookInSeries {
              id
            }
          }
        }
      }
      ... on ResultError {
        error
      }
    }
  }

• Content-type is multipart/mixed
• Client is Apollo Client v3 in https://github.com/eddeee888/graphql-react-template

Demo

Case 1: Slow when loading Book:2

Screen.Recording.2025-10-29.at.12.13.51.am.mov

Case 2: Fast when NOT loading Book:2

Screen.Recording.2025-10-29.at.12.19.59.am.mov

Note: previous and next books come back at different time so the links appear at different time

Case 3: Wrapping both previousBookInSeries and nextBookInSeries in one defer so they appear together

Screen.Recording.2025-10-29.at.12.22.55.am.mov

... on Book @defer {
  previousBookInSeries {
    id
  }
  nextBookInSeries {
    id
  }
}