lndclient: add channel update events

Author: bitromortac

lightning_client.go

@@ -609,6 +609,10 @@ const (
 	// FullyResolvedChannelUpdate indicates that the channel event holds
 	// information about a channel has been fully closed.
 	FullyResolvedChannelUpdate
+
+	// StateChannelUpdate indicates that the channel has updated state or
+	// parameters.
+	StateChannelUpdate
 )
 
 // OpenStatusUpdate is a wrapper for channel status updates following a channel
@@ -649,6 +653,9 @@ type ChannelEventUpdate struct {
 
 	// ClosedChannelInfo holds the channel info for a newly closed channel.
 	ClosedChannelInfo *ClosedChannel
+
+	// ChannelParamsUpdate holds updates to channel parameters.
+	ChannelParamsUpdate *ChannelInfo
 }
 
 // ClosedChannel represents a channel that has been closed.
@@ -2834,6 +2841,17 @@ func (s *lightningClient) getChannelEventUpdate(
 			return nil, err
 		}
 
+	case lnrpc.ChannelEventUpdate_CHANNEL_UPDATE:
+		result.UpdateType = StateChannelUpdate
+		channel := rpcChannelEventUpdate.GetUpdatedChannel()
+
+		result.ChannelParamsUpdate, err = s.newChannelInfo(
+			channel.Channel,
+		)
+		if err != nil {
+			return nil, err
+		}
+
 	default:
 		return nil, fmt.Errorf("unhandled update type: %v",
 			rpcChannelEventUpdate.Type.String())