Improved collection support for extensions

We can enhance extension bindings to have better collection support. i.e. a framework that would allow for many more types to be supported outside of IEnumerable and Arrays.

Interfaces: IAsyncEnumerable, IEnumerable, ICollection, IList (maybe the IReadOnly* variants also)
Concrete types: Collection, List, Array, custom derived types like MyItemList : List

Particularly for `IAsyncEnumerable` - this would allow us to asynchronously fetch the contents as this object is enumerated, yielding a performance benefit for customers. Particularly when they don't enumerate a container completely.

Start by locating the extension binding code that currently handles IEnumerable and arrays, then compare its behavior with IAsyncEnumerable, the other listed interfaces, concrete collection types, and custom derived types. Define the supported collection shapes and verify that asynchronous enumeration can fetch items lazily, especially when a container is only partially enumerated.

Written by the indexing model from the issue text.