/// <summary>
/// Returns a pair of sequences, the first contains the first <paramref name="index"/> of
/// the sequence and the second one contains the rest of them.
/// </summary>
/// <param name="index">The index at which the sequence will be split.</param>
/// <remarks>if <code>index <= 0 || index >= Count</code>, the corresponding part
/// of the result will be empty.</remarks>
public Tuple <RandomAccessSequence <T>, RandomAccessSequence <T> > SplitAt(int index)
{
if (index <= 0)
{
return(Pair.New(Empty, this));
}
if (index >= Count)
{
return(Pair.New(this, Empty));
}
var ftSplit = _ft.SplitAt(index);
return(Pair.New(
new RandomAccessSequence <T>(ftSplit.Item1),
new RandomAccessSequence <T>(ftSplit.Item2)));
}
