src/transformers/models/reformer/modeling_reformer.py/ChunkReformerFeedForward/forward
class ChunkReformerFeedForward:    def forward(self, attention_output):
        return apply_chunking_to_forward(
            self.forward_chunk,
            self.chunk_size_feed_forward,
            self.seq_len_dim,
            attention_output,
        )