Outlook通知REST API订阅所有日历

按照此处的说明进行操作：https://msdn.microsoft.com/en-us/office/office365/api/notify-rest-operations我得到了：

subscribe.php

    <?php
    $access_token=$_SESSION['access_token'];
    $user_email=$_SESSION['user_email'];
    $headers = array(
       "Authorization: Bearer ".$access_token ,
        "Accept: application/json",
        "X-AnchorMailbox: ".$user_email,
        "Content-Type: application/json"
      );
    $data = '{
       "@odata.type":"#Microsoft.OutlookServices.PushSubscription",
       "Resource": "https://outlook.office.com/api/v2.0/me/events",
       "NotificationURL": "https://mywebsite.com/listener.php",
       "ChangeType": "Created, Updated, Deleted",
       "ClientState": "secret"
    }';
    $curl = curl_init('https://outlook.office.com/api/v2.0/me/subscriptions');
    curl_setopt($curl, CURLOPT_HTTPHEADER, $headers);
    curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($curl, CURLOPT_POST, true);
    curl_setopt($curl, CURLOPT_POSTFIELDS,$data);
    $response = curl_exec($curl);
    $httpCode = curl_getinfo($curl, CURLINFO_HTTP_CODE);
    if ($httpCode >= 400)echo "Request returned status: ".$httpCode;
    curl_close($curl);
  $json_vals = json_decode($response, true);
    echo '<pre>'.print_r($json_vals,true).'</pre>';

listener.php

<?php
    if(isset($_REQUEST['validationtoken'])){
        echo $_REQUEST['validationtoken']; // needed only once when subscribing
    } else {
        $headers=getallheaders();
        if (isset($headers['ClientState']) && $headers['ClientState'] == "secret"){
            $body=json_decode(file_get_contents('php://input'));
            file_put_contents(__DIR__.'/listener.text', date("Y-m-d H:i:s").print_r($body,true),FILE_APPEND|LOCK_EX);
        }
    }

我把我的代码放在上面是因为我花了一段时间才弄清楚，也许这对某人有帮助。但是，我仍然有一个问题，上面的代码只为我订阅默认日历。如果我更改其他日历，则不会发生任何事情。

如何使用Outlook通知REST API订阅所有日历，而不仅仅订阅默认日历