rng = torch.Generator()
initial_rng_state = rng.get_state()
datapipe: IterDataPipe = ...
# Some usage of the DataPipe, here maybe yielding the first 5 values
n_iter = 5
it = iter(datapipe)
for _ in range(n_iter):
    next(it)serialized_graph = pickle.dumps(datapipe)

# The serialized object has most of the sufficient information for simple fast-forward (except for initial RNG state)
# It can be deserialized at a later point in time or by a different process
deserialized_graph = pickle.loads(serialized_graph)
# I think `DataLoader` should store `initial_rng_state` that can be saved by the API that we later use
rng_for_deserialized = torch.Generator()
rng_for_deserialized.set_state(initial_rng_state)
n_fastforward = deserialized_graph._number_of_samples_yielded
simple_fast_forward_graph(deserialized_graph, n_fastforward, rng=rng_for_deserialized)
# The while DataPipe graph should have the same state as before serialization, such that:
self.assertEqual(list(it), list(deserialized_graph))  # True