code: function Subscription(stanConnection, subject, qGroup, inbox, opts) {
      this.stanConnection = stanConnection;
      this.subject = subject;
      this.qGroup = qGroup;
      this.inbox = inbox;
      this.opts = opts;
      this.ackInbox = undefined;
      this.inboxSub = undefined;
  }
docs: A NATS streaming subscription is an {event.EventEmitter} representing a subscription to the
  server. The subscription will be ready to receive messages after the Subscription#ready notification.
  fires. Messages are delivered on the Subscription#message(msg) notificatication.
  @param stanConnection
  @param subject
  @param qGroup
  @param inbox
  @param opts
  @constructor
  @fires Subscription#error({Error}), Subscription#unsubscribed, Subscription#ready, Subscription#timeout({Error})
  Subscription#message({Message})