diff --git a/support/bundler/bundler.go b/support/bundler/bundler.go
index 418143d..5f603bd 100644
--- a/support/bundler/bundler.go
+++ b/support/bundler/bundler.go
@@ -214,6 +214,8 @@
 
 // Add adds item to the current bundle. It marks the bundle for handling and
 // starts a new one if any of the thresholds or limits are exceeded.
+// The type of item must be assignable to the itemExample parameter of the NewBundler
+// method, otherwise there will be a panic.
 //
 // If the item's size exceeds the maximum bundle size (Bundler.BundleByteLimit), then
 // the item can never be handled. Add returns ErrOversizedItem in this case.