diff --git a/utils.go b/utils.go
index c9e82e00..71b80de7 100644
--- a/utils.go
+++ b/utils.go
@@ -14,6 +14,7 @@ import (
 	"strings"
 )
 
+// BindKey indicates a default bind key.
 const BindKey = "_gin-gonic/gin/bindkey"
 
 // Bind is a helper function for given interface object and returns a Gin middleware.