feat: derive Clone for mdns::Event

Derive trait `Clone` for `mdns::Event`. This makes cloning its contents without destroying type information possible.



Related #3593.

Pull-Request: #3606.

protocols/mdns/CHANGELOG.md

@@ -1,3 +1,8 @@
+# 0.43.1 [unreleased]
+
+- Derive `Clone` for `mdns::Event`. See [PR 3606].
+
+[PR 3606]: https://github.com/libp2p/rust-libp2p/pull/3606
 # 0.43.0
 
 - Update to `libp2p-core` `v0.39.0`.

protocols/mdns/src/behaviour.rs

@@ -339,7 +339,7 @@ where
 }
 
 /// Event that can be produced by the `Mdns` behaviour.
-#[derive(Debug)]
+#[derive(Debug, Clone)]
 pub enum Event {
     /// Discovered nodes through mDNS.
     Discovered(DiscoveredAddrsIter),
@@ -352,6 +352,7 @@ pub enum Event {
 }
 
 /// Iterator that produces the list of addresses that have been discovered.
+#[derive(Clone)]
 pub struct DiscoveredAddrsIter {
     inner: smallvec::IntoIter<[(PeerId, Multiaddr); 4]>,
 }
@@ -379,6 +380,7 @@ impl fmt::Debug for DiscoveredAddrsIter {
 }
 
 /// Iterator that produces the list of addresses that have expired.
+#[derive(Clone)]
 pub struct ExpiredAddrsIter {
     inner: smallvec::IntoIter<[(PeerId, Multiaddr); 4]>,
 }