title: Convert String (UTF-16) to UTF-8 in C#
body: <p>I need to convert a string to UTF-8 in C#. I've already try many ways but none works as I wanted.
  I converted my string into a byte array and then to try to write it to an XML file (which encoding is UTF-8....) but either I got the same string (not encoded at all) either I got a list of byte which is useless....
  Does someone face the same issue ?</p>
  
  <p>Edit :
  This is some of the code I used :</p>
  
  <pre><code>str= "testé";
  byte[] utf8Bytes = Encoding.UTF8.GetBytes(str);
  return Encoding.UTF8.GetString(utf8Bytes);
  </code></pre>
  
  <p>The result is "testé" or I expected something like "testÃ©"...</p>