fixed cancel call in FindFirstAndCancel

find.go

@@ -10,8 +10,8 @@ func FindFirst[T any](source <-chan T) *T {
 }
 
 func FindFirstAndCancel[T any](source <-chan T, cancel context.CancelFunc) *T {
+	defer cancel()
 	for v := range source {
-		cancel()
 		return &v
 	}
 	return nil