diff --git a/core/modules/big_pipe/src/Render/BigPipeResponse.php b/core/modules/big_pipe/src/Render/BigPipeResponse.php
index 70b637d34d8d6caa708be730a122cbabeae99da9..573b7dcb5ef3e61c79a1e0baf1fd9edc469c59f8 100644
--- a/core/modules/big_pipe/src/Render/BigPipeResponse.php
+++ b/core/modules/big_pipe/src/Render/BigPipeResponse.php
@@ -108,7 +108,7 @@ public function setBigPipeService(BigPipe $big_pipe) {
   /**
    * {@inheritdoc}
    */
-  public function sendContent() {
+  public function sendContent(): static {
     $this->bigPipe->sendContent($this);
 
     // All BigPipe placeholders are processed, so update this response's