code: function processMessage(message) {
        var recipients = Object.keys(message.recipient_status).filter(function(userId) {
          return hook.receipts.reportForStatus.indexOf(message.recipient_status[userId]) !== -1;
        });
  
        if (recipients.length) {
          var identities = [message.sender.user_id].concat(recipients);
          var identityHash = {};
          if (!hook.receipts.identities) {
            createJob(message, recipients, {});
          } else {
            if (!(hook.receipts.identities instanceof Function)) {
              hook.receipts.identities = getUserFromIdentities;
            }
            var getUser = hook.receipts.identities;
            var count = 0;
            identities.forEach(function(userId) {
              getUser(userId, function(err, data) {
                identityHash[userId] = data;
                count++;
                if (count === identities.length) createJob(message, recipients, identityHash);
              })
            });
          }
        }
      }
docs: Process an individual Message and create a job if there
  are matching recipients.