title: How to convert an std::string_view to std::string?
body: <p>An std::string_view is kind of a replacement for <code>char*</code> in C. It's a string that is not copied from place to place, just as char* is just a place in memory that is referenced from time to time.</p>
  <p>However, sometimes we need to transform it in a string for functions that accept a string.</p>
  <p>How do I do that?</p>