minibuffer-completion-help, metadata and determining completions sort order

[T. V. Raman]

I'm having a hard time understanding how one provides custom
metadata to completion-all-completions and friends. Also, looking
at the code in minibuffer-completions-help, I see that the
metadata can provide  a custom sort function -- sounds
good. However the specific use case I want is the ability to not
sort the completions -- Ineed this for implementing Google
Suggest in the minibuffer. I had asked about this many moons ago
and Stefane had said that the code in minibuffer.el would be
changing to support this, assuming the metadata functionality is
to address that  and other use cases?  Anyway, I'd like the
ability to  be able to set things up for Google Suggest so the
completions list goes through unmolested, and as things stand,
Isuppose I could provide a no-op sorter once I figure out to
supply the metadata; however that still feels wasteful since we
would end up traversing the list of completions for no reason ---
there is no option to avoid the sort call in minibuffer-completions-help

-- 
Best Regards,
--raman