In a strongly typed compiled language, how would you do so (in a type-safe and performant way) only knowing that the type is some IEnumerable<T> implementation and not a particular shape that may or may not adhere to the `T this[int i]` and `.Count //of T` contract?
Is using reflection for a quick property check that much of a performance hit? After all, avoiding it leads to footguns like this where someone didn't realize they were traversing an entire array.
