[plt-scheme] removing a finalizer

How do I remove a finalizer
that's been registered via "scheme_register_finalizer"?

Should I use "scheme_remove_all_finalization"?
It's in the source code, but doesn't seem to be in "Inside MzScheme".

(The finalizer frees an external resource if the programmer forgets.
When the programmer properly frees the resource, I'd like to remove the
finalizer, to avoid accumulating hundreds or thousands of them.)

-- 
                                             http://www.neilvandyke.org/