update2

pfosten/vendor/symfony/http-foundation/StreamedResponse.php

@@ -31,8 +31,6 @@ class StreamedResponse extends Response
     private $headersSent;
 
     /**
-     * Constructor.
-     *
      * @param callable|null $callback A valid PHP callback or null to set it later
      * @param int           $status   The response status code
      * @param array         $headers  An array of response headers
@@ -66,37 +64,45 @@ class StreamedResponse extends Response
      * Sets the PHP callback associated with this Response.
      *
      * @param callable $callback A valid PHP callback
+     *
+     * @return $this
      */
     public function setCallback(callable $callback)
     {
         $this->callback = $callback;
+
+        return $this;
     }
 
     /**
      * {@inheritdoc}
      *
      * This method only sends the headers once.
+     *
+     * @return $this
      */
     public function sendHeaders()
     {
         if ($this->headersSent) {
-            return;
+            return $this;
         }
 
         $this->headersSent = true;
 
-        parent::sendHeaders();
+        return parent::sendHeaders();
     }
 
     /**
      * {@inheritdoc}
      *
      * This method only sends the content once.
+     *
+     * @return $this
      */
     public function sendContent()
     {
         if ($this->streamed) {
-            return;
+            return $this;
         }
 
         $this->streamed = true;
@@ -105,19 +111,25 @@ class StreamedResponse extends Response
             throw new \LogicException('The Response callback must not be null.');
         }
 
-        call_user_func($this->callback);
+        \call_user_func($this->callback);
+
+        return $this;
     }
 
     /**
      * {@inheritdoc}
      *
      * @throws \LogicException when the content is not null
+     *
+     * @return $this
      */
     public function setContent($content)
     {
         if (null !== $content) {
             throw new \LogicException('The content cannot be set on a StreamedResponse instance.');
         }
+
+        return $this;
     }
 
     /**
@@ -129,4 +141,16 @@ class StreamedResponse extends Response
     {
         return false;
     }
+
+    /**
+     * {@inheritdoc}
+     *
+     * @return $this
+     */
+    public function setNotModified()
+    {
+        $this->setCallback(function () {});
+
+        return parent::setNotModified();
+    }
 }