fix: correlate downstream receipts with submit responses

gateway/third_party/gocmpp/server.go

@@ -39,7 +39,8 @@ type Packet struct {
 type Response struct {
 	*Packet
 	Packer
-	SeqId uint32
+	SeqId     uint32
+	AfterSend func(error)
 }
 
 type Handler interface {
@@ -420,7 +421,11 @@ func (c *conn) serve() {
 		}
 
 		_, err = c.server.Handler.ServeCmpp(r, r.Packet, c.server.ErrorLog)
-		if err1 := c.finishPacket(r); err1 != nil {
+		err1 := c.finishPacket(r)
+		if r.AfterSend != nil {
+			r.AfterSend(err1)
+		}
+		if err1 != nil {
 			c.server.ErrorLog.Printf(
 				"send response packet failed remote=%v protocol=%s packet_type=%T seq=%d err_type=%T err=%v",
 				c.Conn.RemoteAddr(), c.Conn.Typ, r.Packer, r.SeqId, err1, err1,