嗨我正在使用firebase推送通知来发送推送通知我正在使用CodeIgniter框架我想向所有用户发送通知请帮助。

$data = [
                "notification" => [
                    "body"  => $body,
                    "title" => $title,
                    "url"   => $link,
                    "link"   => $link,
                    "image" => $imgurl,
                    "icon" => 'https://timages/favicon.ico'
                ],
                "priority" =>  "high",
                "data" => [
                    "click_action"  =>  "FLUTTER_NOTIFICATION_CLICK",
                    "id"            =>  "1",
                    "status"        =>  "done",
                    "info"          =>  [
                        "title"  => $title,
                        "url"   => $link,
                        "image"  => $imgurl,
                        "icon" => 'https://timages/favicon.ico'
                    ]
                ],
                "to" => "/topic/all"
                ];

            $ch = curl_init();

            curl_setopt($ch, CURLOPT_URL, 'https://fcm.googleapis.com/fcm/send');
            curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
            curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($data));
            curl_setopt($ch, CURLOPT_POST, 1);

            $headers = array();
            $headers[] = 'Authorization: key=< key >';
            $headers[] = 'Content-Type: application/json';
            curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);

            $result = curl_exec($ch);
            curl_close ($ch);