Allow for callables with beforeSending (#41489)

Author: driesvints

src/Illuminate/Http/Client/PendingRequest.php

@@ -989,11 +989,11 @@ protected function sinkStubHandler($sink)
     public function runBeforeSendingCallbacks($request, array $options)
     {
         return tap($request, function ($request) use ($options) {
-            $this->beforeSendingCallbacks->each->__invoke(
-                (new Request($request))->withData($options['laravel_data']),
-                $options,
-                $this
-            );
+            $this->beforeSendingCallbacks->each(function ($callback) use ($request, $options) {
+                call_user_func(
+                    $callback, (new Request($request))->withData($options['laravel_data']), $options, $this
+                );
+            });
         });
     }