title: Get the last N elements of an array in C#?
body: <p>In C#, what is the most efficient way to return the last N elements of an array?</p>
  
  <p>I am dealing with arrays of hundreds of thousands of elements, and I would prefer an answer that is more efficient than a LINQ based solution.</p>
  
  <p>I would also prefer that the answer is unit tested, to avoid out-by-one errors.</p>