79             if let Some(c) = self.chunk_map.remove(&tsn) {  in pop()
81                 self.n_bytes -= c.user_data.len();  in pop()
82                 return Some(c);  in pop()
143         let n_bytes_acked = if let Some(c) = self.chunk_map.get_mut(&tsn) {  in mark_as_acked()
144             c.acked = true;  in mark_as_acked()
145             c.retransmit = false;  in mark_as_acked()
146             let n = c.user_data.len();  in mark_as_acked()
148             c.user_data.clear();  in mark_as_acked()
162         for c in self.chunk_map.values_mut() {  in mark_all_to_retrasmit()
163             if c.acked || c.abandoned() {  in mark_all_to_retrasmit()
166             c.retransmit = true;  in mark_all_to_retrasmit()