void Main()
{

	Console.WriteLine("\r\n==== Distinct() without  ToArray()====");
	var stopwatch = Stopwatch.StartNew();
	var results = Results().Distinct();
	ProcessResults(results,stopwatch);

	Console.WriteLine("\r\n==== Distinct() with ToArray()====");
	stopwatch = Stopwatch.StartNew();
	results = Results().ToArray().Distinct();
	ProcessResults(results, stopwatch);
}


public void ProcessResults(IEnumerable<string> results, Stopwatch stopWatch) {
	var first = true;
	foreach( var item in results)  {
		if( first) {
			first = false;
			Console.WriteLine("Time to first item: {0} ms",	stopWatch.ElapsedMilliseconds );
		}

		Console.WriteLine("{0}ms :: '{1}' ", stopWatch.ElapsedMilliseconds , item);
	}
	Console.WriteLine("Total Time to enumerate whole set: {0} ms",	stopWatch.ElapsedMilliseconds );

}

public IEnumerable<string> Results() {
	yield return "One";
	System.Threading.Thread.Sleep(100); // each item takes a bit of time.
	yield return "Two";
	System.Threading.Thread.Sleep(100); // each item takes a bit of time.
	yield return "Three";
	System.Threading.Thread.Sleep(100); // each item takes a bit of time.
	yield return "Four";
	System.Threading.Thread.Sleep(100); // each item takes a bit of time.
	yield return "Five";
	System.Threading.Thread.Sleep(100); // each item takes a bit of time.
	yield return "Six";
	System.Threading.Thread.Sleep(100); // each item takes a bit of time.
	yield return "Seven";
	System.Threading.Thread.Sleep(100); // each item takes a bit of time.
	yield return "One";
}

/** RESULTS:

    ==== Distinct() without  ToArray()====
    Time to first item: 1 ms
    1ms :: 'One'
    102ms :: 'Two'
    203ms :: 'Three'
    303ms :: 'Four'
    403ms :: 'Five'
    504ms :: 'Six'
    605ms :: 'Seven'
    Total Time to enumerate whole set: 706 ms

    ==== Distinct() with ToArray()====
    Time to first item: 703 ms
    703ms :: 'One'
    703ms :: 'Two'
    703ms :: 'Three'
    703ms :: 'Four'
    703ms :: 'Five'
    703ms :: 'Six'
    703ms :: 'Seven'
    Total Time to enumerate whole set: 703 ms


*/