_notifyUser(room, notification, { fromCluster = true } = {}) {
    const channels = [];
    const hotelClerkRoom = this.module.hotelClerk.rooms.get(room);

    if (hotelClerkRoom !== undefined) {
      for (const [id, channel] of hotelClerkRoom.channels.entries()) {
        const match =
          channel.users === "all" || channel.users === notification.user;
        const executeOnNode = fromCluster ? channel.cluster : true;

        if (executeOnNode && match) {
          channels.push(id);
        }
      }
    }

    if (channels.length === 0) {
      return Bluebird.resolve();
    }

    return this._dispatch("notify:user", channels, notification);
  }
Broadcast a notification about a user entering or leaving
the provided room

@param {string} room - Room entered or left
@param {UserNotification} notification
@param {object} content - Notification additional informations

@returns {Promise}