diagnostics: disable nginx reverse proxy buffering on configd streams

src/opnsense/mvc/app/controllers/OPNsense/Base/ApiControllerBase.php

@@ -227,6 +227,8 @@ protected function configdStream(
     ) {
         $response = (new Backend())->configdpStream($action, $params, $poll_timeout);
 
+        /* disable nginx reverse proxy buffering so streamed configd output is delivered in real time */
+        $headers[] = 'X-Accel-Buffering: no';
         foreach ($headers as $header) {
             $parts = explode(':', $header, 2);
             $this->response->setHeader($parts[0], ltrim($parts[1]));

src/opnsense/mvc/app/controllers/OPNsense/Diagnostics/Api/LogController.php

@@ -99,8 +99,7 @@ public function __call($name, $arguments)
                     [$offset, $searchPhrase, $module, $scope, $severities],
                     [
                         'Content-Type: text/event-stream',
-                        'Cache-Control: no-cache',
-                        'X-Accel-Buffering: no' /* disable nginx reverse proxy buffering for SSE streams to ensure real-time delivery */
+                        'Cache-Control: no-cache'
                     ],
                     60 /* XXX */
                 );

src/opnsense/mvc/app/controllers/OPNsense/Diagnostics/Api/TrafficController.php

@@ -55,7 +55,7 @@ public function streamAction($poll_interval = 1)
             [$poll_interval],
             [
                 'Content-Type: text/event-stream',
-                'Cache-Control: no-cache',
+                'Cache-Control: no-cache'
             ],
             $poll_interval + 1
         );