title: rvalue for a std::string parameter
body: <p>What's the difference in practice between LVALUE and RVALUE in the following code when I pass the text?
  I mean, in this specific case of a string (where the string is a string literal), is there any benefit of using RVALUE (&amp;&amp;)?</p>
  
  <pre><code>void write_Lvalue(const std::string &amp;text) {
      //...
  }
  
  void write_Rvalue(const std::string &amp;&amp;text) {
      //...
  }
  
  int main() {
      write_Lvalue("writing the Lvalue");
      write_Rvalue("writing the Rvalue");
  }
  </code></pre>