6 files changed, 15 insertions, 2 deletions

diff --git a/src/transport/libp2p/tests.rs b/src/transport/libp2p/tests.rs
index 9f013c2..5d08190 100644
--- a/src/transport/libp2p/tests.rs
+++ b/src/transport/libp2p/tests.rs
@@ -61,6 +61,7 @@ fn status() -> ParsedMessage {
         leaving: false,
         announcing: false,
         reaches: None,
+        round_trips: None,
     })
 }
 
diff --git a/src/transport/mod.rs b/src/transport/mod.rs
index 85f69f5..e81adfb 100644
--- a/src/transport/mod.rs
+++ b/src/transport/mod.rs
@@ -210,6 +210,11 @@ pub(crate) struct Status {
     /// of the members it has an active session with that answer, sorted. In keepalive STATUSes and
     /// their replies, and when it changed; not in announcements of heads (None).
     pub(crate) reaches: Option<Vec<u64>>,
+    /// The round trip to each member in `reaches`, in its order, as a bucket
+    /// (`swarm::rtt::bucket`): which of a member's possible parents in a writer's tree
+    /// is the faster (`swarm::tree`). With `reaches`; None otherwise.
+    #[serde(with = "serde_bytes")]
+    pub(crate) round_trips: Option<Vec<u8>>,
 }
 
 /// Cheap to clone: large parts are shared (`bytes::Bytes`).
diff --git a/src/transport/mycelium/mod.rs b/src/transport/mycelium/mod.rs
index 3552edf..7bae0a7 100644
--- a/src/transport/mycelium/mod.rs
+++ b/src/transport/mycelium/mod.rs
@@ -719,6 +719,7 @@ mod tests {
             leaving: false,
             announcing: false,
             reaches: None,
+            round_trips: None,
         };
         let payload = wire::encode(&ParsedMessage::StatusReply(status.clone())).unwrap();
         // Mycelium's message data: a length byte, the topic, then our payload.
diff --git a/src/transport/paths.rs b/src/transport/paths.rs
index 8c03b1f..aca0684 100644
--- a/src/transport/paths.rs
+++ b/src/transport/paths.rs
@@ -1619,6 +1619,7 @@ mod tests {
             leaving: false,
             announcing: false,
             reaches: None,
+            round_trips: None,
         })
     }
 
diff --git a/src/transport/sim.rs b/src/transport/sim.rs
index 12f3885..06f15f6 100644
--- a/src/transport/sim.rs
+++ b/src/transport/sim.rs
@@ -434,6 +434,7 @@ mod tests {
             leaving: false,
             announcing: false,
             reaches: None,
+            round_trips: None,
         })
     }
 
diff --git a/src/transport/wire.rs b/src/transport/wire.rs
index 580712e..769545c 100644
--- a/src/transport/wire.rs
+++ b/src/transport/wire.rs
@@ -14,7 +14,7 @@ use super::{EncodedMessage, MessageKind, ParsedMessage};
 
 /// The wire format's version, the first byte of every payload. Bump it with every change
 /// to a message type or a codec (`golden_bytes` fails then).
-pub(crate) const VERSION: u8 = 34;
+pub(crate) const VERSION: u8 = 35;
 
 /// What the second byte of a payload says.
 fn tag(kind: MessageKind) -> u8 {
@@ -384,6 +384,7 @@ pub(crate) fn samples() -> Vec<ParsedMessage> {
         leaving: false,
         announcing: false,
         reaches: None,
+        round_trips: None,
     };
     let proof = IdentityProof {
         key: [8; 32],
@@ -570,6 +571,7 @@ mod tests {
             leaving: false,
             announcing: false,
             reaches: None,
+            round_trips: None,
         };
         let decoded =
             decode(&encode(&ParsedMessage::StatusReply(status.clone())).unwrap()).unwrap();
@@ -595,6 +597,7 @@ mod tests {
             leaving: false,
             announcing: false,
             reaches: None,
+            round_trips: None,
         };
         assert!(decode(&encode(&ParsedMessage::Status(status)).unwrap()).is_err());
     }
@@ -695,10 +698,11 @@ mod tests {
             leaving: false,
             announcing: true,
             reaches: None,
+            round_trips: None,
         });
         assert_eq!(
             hex(&encode(&status).unwrap()),
-            format!("{v}03989290c400{epoch_hex}01c3c2c2c3c0")
+            format!("{v}03999290c400{epoch_hex}01c3c2c2c3c0c0")
         );
 
         let who = ParsedMessage::Who(IdentityProof {