I will do for your advice, I will send a letter. This question is not critical to the business. But this issue is not covered in the help file and documentation. I think not only I would be interested to know the answer.
i find in Qlik Sense help for developer intresting thing.
We can create with Virtual Proxy API - Load balancing module. And there create own rule load balancing, authentification and other. Have any one more info about this API. If have exapmles it whas be prefect