code: function getThreadOwner (psid) {  
    return new Promise (async (resolve, reject) => {    
      if (!psid) {
        reject('PSID required to identify the thread to get owner for');
      }
      
      try {
        let request_options = {
          'path': '/me/thread_owner',
          'qs': {'recipient': psid}
        };
  
        let response = await this.sendGraphRequest(request_options);
        resolve(response);
      } catch (e) {
        reject(e);
      }
    });
  }
docs: Retrieves the app ID of the current [thread owner](https://developers.facebook.com/docs/messenger-platform/handover-protocol/take-thread-control).
  @param  {Integer}  psid  The PSID of the user whose thread you want to get the thread owner of.
  @param  {String}   metadata   _Optional._ An arbitrary string that will be delivered to the target app with the `messaging_handovers` webhook event.
  @return {Promise}  The API response
  @memberof  Client#
  @example
  let psid = 1008372609250235
  Client.getThreadOwner(psid)
  .then(res => {
  console.log(res);
  // {
  //   "data": [{
  //     "thread_owner": {
  //       "app_id": "1719933678308212"
  //     }
  //   }]
  // }
  });