title: What is the prettiest way to convert time_point to string?
body: <p>Simple question, how to properly convert <code>std::chrono::time_point</code> to a <code>std::string</code> with as little code as possible?</p>
  
  <p>Notes: I don't want to use <code>cout</code> it with <code>put_time()</code>. C++11 and C++14 solutions are accepted.</p>