[Click] finding pullers downstream

[Ian Rose]

Hello -

Suppose I have a configuration something like this:

FromDevice(foo) -> a::Queue -> Print -> b::Discard;

Now, suppose that I want to write an element that, given a starting 
point (which would be 'a::Queue' in this case) can search downstream and 
find the original puller (which would be 'b::Discard' in this case).  Is 
this possible?  I don't think its as simple as just searching for the 
first downstream 'pull' element as that would return the Print element 
which is not what I want.

I'm trying to do this so that, during execution, I can write new values 
to b.tickets and thereby change the scheduling priorities of different 
paths (useless in this configuration since there is only 1 path, but you 
get the idea).

Thanks!
- Ian