[sigc] Marshallers Vs. Accumulators

[Paul Davis <pjdavis homer biomed-eng uiowa edu>]

I've become rather confused about intended way to collect multiple 
return values from different slots for the same signal.

The docs online and in the package both talk about using Marshallers, 
but a simple grep on the source tree doesn't reveal any class or method 
having to do with Marshallers as far as I can tell.

I did bump into something that looks similar called accumulators that do 
exist in the source tree.

Are the docs just wrong and I should be using accumulators now?

Thanks,
Paul Davis