Option to send server time in connect result (#379)

_examples/recovery_mode_cache/readme.md

@@ -1,7 +1,10 @@
-Demonstration on using cache recovery mode.
+Demonstration of using cache recovery mode.
 
 ```
 go run main.go
 ```
 
 Then go to http://localhost:8000 
+
+The latest message in channel is delivered to a subscriber immediately after subscription so that client gets an
+actual state immediately from publication history.

client.go

@@ -2331,6 +2331,9 @@ func (c *Client) connectCmd(req *protocol.ConnectRequest, cmd *protocol.Command,
 	if c.transport.Emulation() {
 		res.Node = c.node.ID()
 	}
+	if c.node.config.ClientConnectIncludeServerTime {
+		res.Time = time.Now().UnixMilli()
+	}
 
 	// Client successfully connected.
 	c.mu.Lock()

client_test.go

@@ -269,6 +269,7 @@ func TestClientConnectNoCredentialsNoToken(t *testing.T) {
 func TestClientConnectContextCredentials(t *testing.T) {
 	node := defaultTestNode()
 	defer func() { _ = node.Shutdown(context.Background()) }()
+	node.config.ClientConnectIncludeServerTime = true
 
 	transport := newTestTransport(func() {})
 	ctx := context.Background()
@@ -284,6 +285,7 @@ func TestClientConnectContextCredentials(t *testing.T) {
 	result := extractConnectReply(rwWrapper.replies)
 	require.Equal(t, false, result.Expires)
 	require.Equal(t, uint32(0), result.Ttl)
+	require.NotZero(t, result.Time)
 	require.True(t, client.authenticated)
 	require.Equal(t, "42", client.UserID())
 }

config.go

@@ -20,6 +20,10 @@ type Config struct {
 	// aggregation. It's not reasonable to have it less than one second.
 	// Zero value means 60 * time.Second.
 	NodeInfoMetricsAggregateInterval time.Duration
+	// ClientConnectIncludeServerTime tells Centrifuge to append `time` field to Connect result of client protocol.
+	// This field contains Unix timestamp in milliseconds and represents current server time. By default, server time
+	// is not included.
+	ClientConnectIncludeServerTime bool
 	// ClientPresenceUpdateInterval sets an interval how often connected
 	// clients update presence information.
 	// Zero value means 25 * time.Second.