title: Fastest way of converting IPv6 dotted format string to colon format ? C#
body: <p>What is the fastest way of converting the dotted format of the following IP from version 6 
  to colon format??</p>
  
  <p>128.91.45.157.220.40.101.10.10.1.252.87.22.200.31.255</p>
  
  <p>I just typed the IP above randomly.</p>
  
  <p>Thanks</p>