lnrpc+rpcserver: populate experimental MPP fields in ListPayment rpc

rpcserver.go

@@ -4379,13 +4379,25 @@ func (r *rpcServer) ListPayments(ctx context.Context,
 			return nil, err
 		}
 
+		htlcs := make([]*lnrpc.HTLCAttempt, 0, len(payment.HTLCs))
+		for _, dbHTLC := range payment.HTLCs {
+			htlc, err := r.routerBackend.MarshalHTLCAttempt(dbHTLC)
+			if err != nil {
+				return nil, err
+			}
+
+			htlcs = append(htlcs, htlc)
+		}
+
 		paymentHash := payment.Info.PaymentHash
+		creationTimeNS := routerrpc.MarshalTimeNano(payment.Info.CreationTime)
 		paymentsResp.Payments = append(paymentsResp.Payments, &lnrpc.Payment{
 			PaymentHash:     hex.EncodeToString(paymentHash[:]),
 			Value:           satValue,
 			ValueMsat:       msatValue,
 			ValueSat:        satValue,
 			CreationDate:    payment.Info.CreationTime.Unix(),
+			CreationTimeNs:  creationTimeNS,
 			Path:            path,
 			Fee:             int64(route.TotalFees().ToSatoshis()),
 			FeeSat:          int64(route.TotalFees().ToSatoshis()),
@@ -4393,6 +4405,7 @@ func (r *rpcServer) ListPayments(ctx context.Context,
 			PaymentPreimage: hex.EncodeToString(preimage[:]),
 			PaymentRequest:  string(payment.Info.PaymentRequest),
 			Status:          status,
+			Htlcs:           htlcs,
 		})
 	}