perf(group): reduce websocket fanout serialization

server/hdl_websock.go

@@ -105,7 +105,9 @@ func (sess *Session) readLoop() {
 		atomic.StoreInt64(&sess.lastAction, types.TimeNow().UnixNano())
 		_ = sess.ws.SetReadDeadline(time.Now().Add(pongWait))
 		statsInc("IncomingMessagesWebsockTotal", 1)
+		dispatchStarted := time.Now()
 		sess.dispatchRaw(raw)
+		immetrics.ObserveWSReadDispatch(dispatchStarted)
 	}
 }
 
@@ -160,6 +162,11 @@ func (sess *Session) writeLoop() {
 				if isAcceptedCtrl(v) {
 					immetrics.ObserveCtrlACKDelivery("write", v.Timestamp)
 				}
+			case sharedServerMessage:
+				statsAddHistSample("OutgoingMessageSize", float64(len(v)))
+				if !sess.sendMessage([]byte(v)) {
+					return
+				}
 			default: // serialized message
 				if !sess.sendMessage(v) {
 					return