feat: deferred queries in loader

[imp-dance]

Deferring queries

You can defer queries by using the deferredQueries argument in createLoader (or createUseLoader). These queries are passed as the second argument to transform which has to be used to access the deferred queries in your loaded component.

Example usage:

const loader = createLoader({
  queries: () => [useImportantQuery()] as const,
  deferredQueries: () => [useSlowButNotImportantQuery()] as const,
  transform: (queries, deferredQueries) => ({
    important: queries[0].data,
    not_important: deferredQueries[0].data,
  }),
});
const Component = withLoader((props, loaderData) => {
  const { important, not_important } = loaderData;
  // not_important could be undefined
  return (
    <div>
      {important.person.name}
      {not_important ? "it has resolved : "some fallback"}
    </div>
  )
}, loader);

[imp-dance]

LGTM 🚀