_propagateMessageToListeners (msg, chan, transform = this._transform) {
    const listenerGroups = Object.values(this._listeners)

    for (let i = 0; i < listenerGroups.length; i++) {
      WSv2._notifyListenerGroup(listenerGroups[i], msg, transform, this, chan)
    }
  }
@param {Array} msg - incoming message
@param {object} chan - channel data
@param {boolean} transform - defaults to internal flag
@private