title: Convert Guid to 2 longs and 2 longs to Guid in c#
body: <p>Guid is a 128bits structure, long is a Int64 so 64 bits structure, therefore Guid can be used to represent two long and two long can be stored in a Guid.</p>
  
  <p>I have been searching several times for a reliable way to perform the transformation of a Guid to 2 longs and the way around, mainly to get a simple way to provide a tracking id to external services.</p>
  
  <p>The objective is to get a reversable way to pass in a single parameter 2 longs, and decode it back later (of course it is not intended to be used "decoded" on the other side). It is like a session id for the external service.</p>