How can you properly implement request deduplication to prevent several genuinely separate identical simultaneous requests for exactly the same particular data from all actually and wastefully hitting your backend server together at once?

Request deduplication properly ensures that if several genuinely separate different parts of your app simultaneously request exactly the same particular piece of data, such as several separate widgets all requesting the exact same specific user profile at essentially the exact same time, only one single actual underlying network request is genuinely actually made, with every one of those separate individual callers all properly sharing that exact same single resulting Future rather than each one wastefully triggering its own genuinely completely separate redundant request, which can meaningfully reduce unnecessary load on your backend server and also genuinely improve your app's own overall perceived performance.

final Map<String, Future<User>> _pendingRequests = {};

Future<User> fetchUser(String id) {
  return _pendingRequests.putIfAbsent(id, () => api.fetchUser(id).whenComplete(() => _pendingRequests.remove(id)));
}