title: How to Remove Duplicate Matches in a MatchCollection
body: <p>In my MatchCollection, I get matches of the same thing. Like this:</p>
  
  <pre><code>string text = @"match match match";
  Regex R = new Regex("match");
  MatchCollection M = R.Matches(text);
  </code></pre>
  
  <p>How does one remove duplicate matches and is it the fastest way possible? </p>
  
  <p><em>Assume "duplicate" here means that the match contains the exact same string.</em></p>