avoid duplicating advertisement of NEW_CONNECTION_ID frames

As well as RETIRE_CONNECTION_ID frames

Author: qdeconinck

quiche/src/cid.rs

@@ -1246,7 +1246,7 @@ impl ConnectionIdentifiers {
     pub fn mark_advertise_new_scid_seq(
         &mut self, path_id: PathId, scid_seq: CIDSeq, advertise: bool,
     ) {
-        if advertise {
+        if advertise && !self.advertise_new_scid_seqs.contains(&(path_id, scid_seq)) {
             self.advertise_new_scid_seqs.push_back((path_id, scid_seq));
         } else if let Some(index) = self
             .advertise_new_scid_seqs
@@ -1264,7 +1264,7 @@ impl ConnectionIdentifiers {
     pub fn mark_retire_dcid_seq(
         &mut self, path_id: PathId, dcid_seq: CIDSeq, retire: bool,
     ) {
-        if retire {
+        if retire && !self.retire_dcid_seqs.contains(&(path_id, dcid_seq)) {
             self.retire_dcid_seqs.push_back((path_id, dcid_seq));
         } else if let Some(index) = self
             .retire_dcid_seqs