public override Slice EncodeComposite(FdbTuple <T1, T2> key, int items)
{
switch (items)
{
case 2: return(key.ToSlice());
case 1: return(FdbTuple.Pack <T1>(key.Item1));
default: throw new ArgumentOutOfRangeException("items", items, "Item count must be either 1 or 2");
}
}