Merge remote-tracking branch 'origin/v3' into v3

# Conflicts:
#	client/noop.go
#	errors/errors_test.go
#	logger/unwrap/unwrap_test.go
#	register/memory/memory_test.go
#	server/noop_test.go
#	service.go
#	util/dns/cache.go
#	util/dns/conn.go
#	util/structfs/metadata_ec2.go
#	util/time/duration.go

register/memory/memory_test.go

@@ -302,19 +302,17 @@ func TestWatcher(t *testing.T) {
 	}
 	defer wc.Stop()
 
+	cherr := make(chan error, 10)
 	var wg sync.WaitGroup
 	wg.Add(1)
 	go func() {
-		for {
-			_, err := wc.Next()
-			if err != nil {
-				t.Fatal("unexpected err", err)
-			}
-			// t.Logf("changes %#+v", ch.Service)
-			wc.Stop()
-			wg.Done()
-			return
+		_, err := wc.Next()
+		if err != nil {
+			cherr <- fmt.Errorf("unexpected err %v", err)
 		}
+		// t.Logf("changes %#+v", ch.Service)
+		wc.Stop()
+		wg.Done()
 	}()
 
 	if err := m.Register(ctx, testSrv); err != nil {