title: std::lock_guard or std::scoped_lock?
body: <p>C++17 introduced a new lock class called <a href="http://en.cppreference.com/w/cpp/thread/scoped_lock/scoped_lock" rel="noreferrer"><code>std::scoped_lock</code></a>. </p>
  
  <p>Judging from the documentation it looks similar to the already existing <code>std::lock_guard</code> class.</p>
  
  <p>What's the difference and when should I use it?</p>