How does hot_standby_feedback work

<div><div>Hello!</div><div> </div><div>My name is Alexander. I am an administarator PostgreSQL.</div><div>I am studying PostgreSQL's 9.6 documentation.</div><div>I am interested in parameter hot_standby_feedback in postgresql.conf</div><div>Can you explain more detail than in documentation for what this parameter is used?</div><div>In what situations the parameter can show itself?</div><div>How to test influence of the parameter on database's behavour.</div><div> </div><div>Regards, Alexander</div></div>