Record the stream and consumer info timestamps

This records the server time when info for streams and
consumers are created so that tools such as the nats cli
can calculate time deltas for last ack, last delivered and
so forth in the context of the server clock.

This will help aleviate problems with client devices experiencing
clock jitter that can show up in user interfaces as negative
seconds since last ack etc

Signed-off-by: R.I.Pienaar <rip@devco.net>

server/consumer.go

@@ -55,6 +55,8 @@ type ConsumerInfo struct {
 	NumPending     uint64          `json:"num_pending"`
 	Cluster        *ClusterInfo    `json:"cluster,omitempty"`
 	PushBound      bool            `json:"push_bound,omitempty"`
+	// TimeStamp indicates when the info was gathered
+	TimeStamp time.Time `json:"ts"`
 }
 
 type ConsumerConfig struct {
@@ -2394,6 +2396,7 @@ func (o *consumer) infoWithSnapAndReply(snap bool, reply string) *ConsumerInfo {
 		NumRedelivered: len(o.rdc),
 		NumPending:     o.checkNumPending(),
 		PushBound:      o.isPushMode() && o.active,
+		TimeStamp:      time.Now().UTC(),
 	}
 
 	// If we are replicated and we are not the leader we need to pull certain data from our store.