do not reallocate waiters

src/client/connector.rs

@@ -509,28 +509,30 @@ impl ClientConnector {
  }
  }
 
+ // TODO: waiters should be sorted by deadline. maybe timewheel?
  fn collect_waiters(&mut self) {
  let now = Instant::now();
  let mut next = None;
 
  for waiters in self.waiters.as_mut().unwrap().values_mut() {
- let mut new_waiters = VecDeque::new();
- while let Some(waiter) = waiters.pop_front() {
- if waiter.wait <= now {
+ let mut idx = 0;
+ while idx < waiters.len() {
+ let wait = waiters[idx].wait;
+ if wait <= now {
  self.stats.timeouts += 1;
+ let waiter = waiters.swap_remove_back(idx).unwrap();
  let _ = waiter.tx.send(Err(ClientConnectorError::Timeout));
  } else {
  if let Some(n) = next {
- if waiter.wait < n {
- next = Some(waiter.wait);
+ if wait < n {
+ next = Some(wait);
  }
  } else {
- next = Some(waiter.wait);
+ next = Some(wait);
  }
- new_waiters.push_back(waiter);
+ idx += 1;
  }
  }
- *waiters = new_waiters;
  }
 
  if next.is_some() {