POST /fcm/send HTTP/1.1
Host: fcm.googleapis.com
Authorization: key=AIzaSyCY0RCcTod86D-nYLOWK4mGT-qZhHDgPXM
Content-Type: application/json; 
Cache-Control: no-cache
Postman-Token: dd0b1b53-2248-7b7b-e97d-1be4cc08141b

{
 "to" : "edQsUefKL1U:APA91bH9C_D4Iqul9iEN42xfoYmbjapH-1CU9CAl2gzUn5cCZc71Bnrtsa2MvBiiW4-9Hato1bZ8DhPm9an0j6MIURIxlh5GZV8ejUk82KylhKN5Kx-GeTAyOYPGNB3HGpCqMlK679JF",
 "collapse_key" : "type_a",
 "notification" : {
     "body" : "¤¤¤å",
     "title": "Title of Your Notification"
     }
  }