message: Use Result's ok() method instead of matching and converting to an Option
diff: @@ -781,10 +781,7 @@ pub struct SubscriptionDeadlineIterator {
  impl Iterator for SubscriptionDeadlineIterator {
  type Item = Message;
  fn next(&mut self) -> Option<Self::Item> {
  - match self.r.recv_timeout(self.to) {
  - Ok(m) => Some(m),
  - _ => None,
  - }
  + self.r.recv_timeout(self.to).ok()
  }
  }
  