public void TryGetFirst ()
{
#region TryGetFirst
var seq = new int[]{0, 1, 2};
int first;
Assert.IsTrue (seq.TryGetFirst (out first));
Assert.IsTrue (0 == first);
seq = new int[]{};
Assert.IsFalse (seq.TryGetFirst (out first));
Assert.IsTrue (0 == first);
#endregion
}