Emit a User and DeviceID in txn message

pubsub/v2.go

@@ -44,6 +44,8 @@ func (*V2Accumulate) Type() string { return "V2Accumulate" }
 // V2TransactionID is emitted by a poller when it sees an event with a transaction ID.
 type V2TransactionID struct {
 	EventID       string
+	UserID        string
+	DeviceID      string
 	TransactionID string
 	NID           int64
 }

sync2/handler2/handler.go

@@ -290,6 +290,8 @@ func (h *Handler) Accumulate(ctx context.Context, userID, deviceID, roomID, prev
 
 			h.v2Pub.Notify(pubsub.ChanV2, &pubsub.V2TransactionID{
 				EventID:       eventID,
+				UserID:        userID,
+				DeviceID:      deviceID,
 				TransactionID: txnID,
 				NID:           nid,
 			})