title: How to format std::chrono durations?
body: <p>Is there a convenient way to format <code>std::chrono::duration</code> to a specified format?</p>
  
  <pre><code>std::chrono::high_resolution_clock::time_point now, then;
  then = std::chrono::high_resolution_clock::now();
  // ...
  now = std::chrono::high_resolution_clock::now();
  auto duration = now - then;
  
  // base in microseconds:
  auto timeInMicroSec =
        std::chrono::duration_cast&lt;std::chrono::microseconds&gt;(duration);
  </code></pre>
  
  <p>How can I format <code>timeInMicroSec</code> like <code>ss::ms::us</code>?</p>