add links messages

Introduce two new wire messages, LINKS and LINKS_REPLY (swarm::links).
A member answers with its links: for each peer, the transport, whether
it’s relayed, the RTT, and whether it’s dormant.  It answers members
only, at most every 5 s.  This bumps wire::VERSION to 7.  Every build
answers, with or without the feature, so every node needs this patch
before the map shows anything beyond its own node.

1 files changed, 1 insertions, 0 deletions

diff --git a/src/api/stats/prometheus.rs b/src/api/stats/prometheus.rs
index 690effa..aef0616 100644
--- a/src/api/stats/prometheus.rs
+++ b/src/api/stats/prometheus.rs
@@ -179,6 +179,7 @@ fn traffic_series(traffic: &PeerTraffic) -> Vec<(&'static str, &'static str, Cou
             (direction, "blob", by.blob),
             (direction, "identity", by.identity),
             (direction, "paths", by.paths),
+            (direction, "links", by.links),
         ]
     };
     let mut series = Vec::new();