title: How to convert boost::string_view to std::string_view?
body: <p>I'm using a boost library which uses <code>boost::string_view</code>. However, I would like to use <code>std::string_view</code> in my code.<br>
  <strong>Q:</strong> What's the best way to convert between these two?  </p>
  
  <p>At the moment I'm using:</p>
  
  <pre><code>void foo(std::string_view sv) {
  # ...
  }
  void foo(boost::string_view bsv) {
    foo(std::string(bsv));
  }
  </code></pre>
  
  <p>But this creates an unnecessary string.</p>