This reverts a change in the internal representation of `BufferView` which has potentially significant performance consequences. We might want to make this change, but we need to carefully evaluate the performance consequences first.
This reverts commit 6900c61344048242878ccbb9b79b0a47b2b75e80.
* Refactor BufferView to use typealias "Index" for Collection protocol methods
* Refactor BufferView to use "Index" consistently both within and outside of Collection extension methods.
* Remove comments in BufferView
* Revert the position defined of Index and make it clear that it is part of the Collection conformance in BufferView
* Move count among the Collection conformance in BufferView
