message: Remove assert in output_path()
  fixes
diff: @@ -1031,7 +1031,6 @@ impl Connection {
  if let Some(t) = token {
  tokens.push(t);
  }
  - assert!(encoder.len() <= self.pmtu());
  if out_bytes.len() + encoder.len() == self.pmtu() {
  // No more space for frames.
  break;
  