title: How to add mutable_content in APNS payload using Firebase Notifications console?
body: <p>Not able to figure out how to send mutable_content=true in aps dictionary. This is the json payload which i recieve when i send notification from firebase messaging console</p>
  
  <pre><code>{
      aps =     {
          alert =         {
              body = "50% off on booking ";
              title = "CompanyName 50% coupon ABC50OFF";
          };
          sound = default;
      };
      "attachment-url" = "https://www.xxxxxxxxx.com/campaign/images_thumb/Toyota-Fortuner-AT.jpg";
      "click_action" = reminder;
      "content_available" = 1;
      "gcm.message_id" = "0:1491225835295720%a84b45aaa84b45aa";
      "gcm.n.e" = 1;
      "gcm.notification.sound2" = default;
      "google.c.a.c_id" = 3829383583613273032;
      "google.c.a.e" = 1;
      "google.c.a.ts" = 1491225835;
      "google.c.a.udt" = 0;
      "mutable_content" = 1;
  }
  </code></pre>