bitfield-dist: fix state update on gossip (#2817)

* bitfield-dist: fix state update on gossip

* fixes

* doc fixes

* oops

* 2 lines of code change

polkadot/node/network/bitfield-distribution/src/lib.rs

@@ -345,12 +345,6 @@ where
 			// check interest in the peer in this message's relay parent
 			if view.contains(&message.relay_parent) {
 				let message_needed = job_data.message_from_validator_needed_by_peer(&peer, &validator);
-				// track the message as sent for this peer
-				job_data.message_sent_to_peer
-					.entry(peer.clone())
-					.or_default()
-					.insert(validator.clone());
-
 				if message_needed {
 					Some(peer.clone())
 				} else {
@@ -362,6 +356,15 @@ where
 		})
 		.collect::<Vec<PeerId>>();
 	let interested_peers = util::choose_random_sqrt_subset(interested_peers, MIN_GOSSIP_PEERS);
+	interested_peers.iter()
+		.for_each(|peer|{
+			// track the message as sent for this peer
+			job_data.message_sent_to_peer
+				.entry(peer.clone())
+				.or_default()
+				.insert(validator.clone());
+		});
+
 	drop(_span);
 
 	if interested_peers.is_empty() {