- rewrite existing methods in terms of the new ones
- don't allocate multiple 0-length arrays

nit:
- clarify a couple of doc comments e.g. using `<paramref/>`
- move an error message into a resource
 - pass parameter names into new resource
- rename parameters for consistency e.g. `inputLength` -> `count`

Also name literal `int` parameters.

- more `var`
- move `count` parameters to the end

Also added a test covering the new overloads.