Zero-copy CameraFile transfer?

Hi, I've been looking through the libgphoto2 API for a way to
implement zero-copy transfers such as through Linux's sendfile(2)
system call, but it seems there isn't currently an exposed way to get
at an open CameraFile's file descriptor to pull this off.

I do see that the CameraFile object has an fd member in it that
gp_file_slurp() references, but the comments say that gp_file_slurp()
is an internal function and that gp_file_open() is now deprecated.

Is there a cleaner way to do this?  Or should I not play with matches?  :)

Thank you!

        =-ddt->