title: C#. Fastest Regex to match any string
body: <p>Quite simple. What's the fastest regex that will return true for any input?</p>
  
  <p>Edit: why the down votes? Seems like a very legitimate question. I use a function that takes a regex filter and I want to know what will make it match everything the most quickly.  "Not using a regex" is not an answer. </p>