Add optional last_rapid_gossip_sync_timestamp field to NetworkGraph.

Author: arik-so

lightning/src/routing/network_graph.rs

@@ -127,6 +127,7 @@ pub struct NetworkGraph {
 	// Lock order: channels -> nodes
 	channels: RwLock<BTreeMap<u64, ChannelInfo>>,
 	nodes: RwLock<BTreeMap<NodeId, NodeInfo>>,
+	last_rapid_gossip_sync_timestamp: Option<u32>,
 }
 
 impl Clone for NetworkGraph {
@@ -137,6 +138,7 @@ impl Clone for NetworkGraph {
 			genesis_hash: self.genesis_hash.clone(),
 			channels: RwLock::new(channels.clone()),
 			nodes: RwLock::new(nodes.clone()),
+			last_rapid_gossip_sync_timestamp: self.last_rapid_gossip_sync_timestamp.clone(),
 		}
 	}
 }
@@ -990,7 +992,9 @@ impl Writeable for NetworkGraph {
 			node_info.write(writer)?;
 		}
 
-		write_tlv_fields!(writer, {});
+		write_tlv_fields!(writer, {
+			(1, self.last_rapid_gossip_sync_timestamp, option),
+		});
 		Ok(())
 	}
 }
@@ -1014,12 +1018,18 @@ impl Readable for NetworkGraph {
 			let node_info = Readable::read(reader)?;
 			nodes.insert(node_id, node_info);
 		}
-		read_tlv_fields!(reader, {});
+
+		let mut last_rapid_gossip_sync_timestamp: Option<u32> = None;
+
+		read_tlv_fields!(reader, {
+			(1, last_rapid_gossip_sync_timestamp, option),
+		});
 
 		Ok(NetworkGraph {
 			genesis_hash,
 			channels: RwLock::new(channels),
 			nodes: RwLock::new(nodes),
+			last_rapid_gossip_sync_timestamp,
 		})
 	}
 }
@@ -1053,6 +1063,7 @@ impl NetworkGraph {
 			genesis_hash,
 			channels: RwLock::new(BTreeMap::new()),
 			nodes: RwLock::new(BTreeMap::new()),
+			last_rapid_gossip_sync_timestamp: None,
 		}
 	}