diff --git a/pkg/machine/misc.go b/pkg/machine/misc.go
index bf3b503..91d8be5 100644
--- a/pkg/machine/misc.go
+++ b/pkg/machine/misc.go
@@ -199,6 +199,7 @@ type (
 	indexWhen map[string][]*whenBinding
 	// map of (single) state names to a list of bindings
 	indexStateCtx map[string][]context.CancelFunc
+	indexEventCh  map[string][]chan *Event
 )
 
 type whenBinding struct {