node: sketch of debug node logic

types/event_bus.go

@@ -244,9 +244,9 @@ func (NopEventBus) Subscribe(
 	ctx context.Context,
 	subscriber string,
 	query tmpubsub.Query,
-	out chan<- interface{},
-) error {
-	return nil
+	outCapacity ...int,
+) (Subscription, error) {
+	return nil, nil
 }
 
 func (NopEventBus) Unsubscribe(ctx context.Context, args tmpubsub.UnsubscribeArgs) error {
@@ -324,3 +324,11 @@ func (NopEventBus) PublishEventBlockSyncStatus(data EventDataBlockSyncStatus) er
 func (NopEventBus) PublishEventStateSyncStatus(data EventDataStateSyncStatus) error {
 	return nil
 }
+
+func (NopEventBus) NumClientSubscriptions(clientID string) int {
+	return 0
+}
+
+func (NopEventBus) NumClients() int {
+	return 0
+}