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

metadata/metadata_test.go

@@ -83,6 +83,7 @@ func TestPassing(t *testing.T) {
 	if ok {
 		t.Fatalf("create outgoing context")
 	}
+	_ = md
 
 	ctx = NewOutgoingContext(ctx, New(1))
 	testCtx(ctx)