title: Capture profile of fragment of JavaScript program
body: <p>I have a piece of code which is crazy time consuming (reducer that does hardcore objects cloning etc...).</p>
  
  <p>Is there a way to start/stop via JavaScript profiling in Chrome, or make some marks, so that I can easily spot where is the code I am interested in inside long profiler's data?</p>
  
  <p>E.g.</p>
  
  <pre><code>// start profiling here e.g. Profiler.startProfiler()
  callHardcoreFunction();
  // end profiling here e.g. Profiler.startProfiler()
  </code></pre>