如何使用OneSignal接口和PHP在推送通知中发送“附加数据”

<?php
function sendMessage() {
    $content = array(
        "en" => 'Notification message'
    );

    $fields = array(
        'app_id' => 'YOUR_APP_ID',
        'included_segments' => array('All'),
        'contents' => $content,
        'data' => array('key' => 'value') // 附加数据
    );

    $fields = json_encode($fields);

    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, "https://onesignal.com/api/v1/notifications");
    curl_setopt($ch, CURLOPT_HTTPHEADER, array(
        'Content-Type: application/json; charset=utf-8',
        'Authorization: Basic YOUR_REST_API_KEY'
    ));
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
    curl_setopt($ch, CURLOPT_HEADER, FALSE);
    curl_setopt($ch, CURLOPT_POST, TRUE);
    curl_setopt($ch, CURLOPT_POSTFIELDS, $fields);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);

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

    return $response;
}

$response = sendMessage();
echo $response;
?>