discover: Implement Clone for Change

Implements Clone for discover::Change, if the underlying key and value
both implement clone.

This is convenient for use-cases where a single change needs to be
duplicated, and sent to multiple discover streams.

tower/src/discover/mod.rs

@@ -104,3 +104,16 @@ pub enum Change<K, V> {
  /// The service identified by key `K` disappeared.
  Remove(K),
 }
+
+impl<K, V> Clone for Change<K, V>
+where
+ K: Clone,
+ V: Clone,
+{
+ fn clone(&self) -> Self {
+ match self {
+ Change::Insert(k, v) => Change::Insert(k.clone(), v.clone()),
+ Change::Remove(k) => Change::Remove(k.clone()),
+ }
+ }
+}