subscribe(cmd, nodeID) {
		const t = this.getTopicName(cmd, nodeID);
		const handler = msg => this.receive(cmd, msg);
		this.subscriptions.push({ topic: t, handler });

		this.bus.on(t, handler);
		return this.broker.Promise.resolve();
	}
Subscribe to a command

@param {String} cmd
@param {String} nodeID

@memberof FakeTransporter