Ensure that discovery producer is stopped

discovery/rendezvous.go

@@ -192,8 +192,18 @@ func (r *Rendezvous) Discover(
 				log.Debug("converted enr to", "ENODE", n.String())
 				if err != nil {
 					log.Warn("error converting enr record to node", "err", err)
+					continue
+				}
+				select {
+				case found <- n:
+				case newPeriod, ok := <-period:
+					// closing a period channel is a signal to producer that consumer exited
+					ticker.Stop()
+					if !ok {
+						return nil
+					}
+					ticker = time.NewTicker(newPeriod)
 				}
-				found <- n
 			}
 		}
 	}

peers/peerpool.go

@@ -201,12 +201,12 @@ func (p *PeerPool) stopDiscovery(server *p2p.Server) {
 		return
 	}
 
+	if err := p.discovery.Stop(); err != nil {
+		log.Error("discovery errored when stopping", "err", err)
+	}
 	for _, t := range p.topics {
 		t.StopSearch(server)
 	}
-	if err := p.discovery.Stop(); err != nil {
-		log.Error("discovery errored when was closed", "err", err)
-	}
 
 	p.mu.Lock()
 	p.timeout = nil