Re: [PATCH] ref-filter: format iteratively with lexicographic refname sorting

> But there is one exception here where we _can_ get away with sorting
> refs while streaming: ref backends sort references returned by their
> iterators in lexicographic order. So if the following conditions are all
> true we can do iterative streaming:
>
>   - The caller uses at most a single name pattern. Otherwise we'd have
>     to sort results from multiple invocations of the iterator.
>
>   - There must be at most a single sorting specification, as otherwise
>     we're not using plain lexicographic ordering.
>
>   - The sorting specification must use the "refname".
>
>   - The sorting specification must not be using any flags, like
>     case-insensitive sorting.