feat: use the old serialisation as default, add some docs

sn_transfers/src/cashnotes/unique_keys.rs

@@ -38,7 +38,12 @@ impl DerivationIndex {
     }
 }
 
-#[derive(Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
+// NB TODO remove Serialize impl when enough nodes have updated to support the new serialisation format!
+// cf below for the new Serialize impl
+/// A Unique Public Key is the unique identifier of a CashNote and its SignedSpend on the Network when it is spent.
+/// It is the mechanism that makes transactions untraceable to the real owner (MainPubkey).
+/// It is the equivalent to using a different key for each transaction in bitcoin.
+#[derive(Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash, Serialize)]
 pub struct UniquePubkey(PublicKey);
 
 impl UniquePubkey {
@@ -69,14 +74,16 @@ impl UniquePubkey {
     }
 }
 
-/// Custom implementation of Serialize and Deserialize for UniquePubkey to make it an actionable
-/// hex string that can be copy pasted in apps, instead of a useless array of numbers
-/// Caveat: this is slower than the default implementation
-impl Serialize for UniquePubkey {
-    fn serialize<S: serde::Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
-        serializer.serialize_str(&self.to_hex())
-    }
-}
+// NB TODO enable this when enough nodes have updated to support the new serialisation format!
+// cf above (remove the derived Serialize impl and enable this one)
+// /// Custom implementation of Serialize and Deserialize for UniquePubkey to make it an actionable
+// /// hex string that can be copy pasted in apps, instead of a useless array of numbers
+// /// Caveat: this is slower than the default implementation
+// impl Serialize for UniquePubkey {
+//     fn serialize<S: serde::Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
+//         serializer.serialize_str(&self.to_hex())
+//     }
+// }
 
 impl<'de> Deserialize<'de> for UniquePubkey {
     fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>