Returns element at specified position
val idx: Idx[Char] = ('A' <> 'Z').stream.pack idx(1).tp // Prints: B idx(4).tp // Prints: E
Returns a Stream of all elements
The element order is same as in the Idx itself
val l: Idx[Char] = ('a' <> 'g').stream.pack l.stream.tp // Prints Stream(a, b, c, d, e, f, g)