Re: [PATCHv2 1/7] list-objects.c: factor out traverse_trees_and_blobs

> With traverse_trees_and_blobs factored out of the main traverse function,
> the next patch can introduce an in-order revision walking with ease.
>
> In the next patch we'll call `traverse_trees_and_blobs` from within the
> loop walking the commits, such that we'll have one invocation of that
> function per commit.  That is why we do not want to have memory allocations
> in that function, such as we'd have if we were to use a strbuf locally.
> Pass a strbuf from traverse_commit_list into the blob and tree traversing
> function as a scratch pad that only needs to be allocated once.