[Stackless] tracing Stackless events

[David Wyand]

Hi Andrew.

>   - I can't figure out how to get all tasklets in the system, so I
> only get
>      all the ones which are "named" in my WeakKeyDict
>
> Possible solution: tell me how to do that.  Failing that, implement a
> function which iterates over all tasklets.
>

I also needed to get a list of all tasklets in the system for my Stackless 
and Twisted example (http://www.gnometech.com/pythonproducts.shtml).  I 
couldn't find a way to do it directly so I ended up using the gc to build a 
list.  If you look in the zone.py file in my example under the 
GetTaskletsForWeb() method you'll see how I accomplished this.  I also have 
a custom Tasklet class and that's where the 'context' and 'parentObj' 
attributes come from in the list generation.

The main downside is the performance hit I take while working with the gc. 
There is a noticeable pause in my event loop while performing a manual 
gc.collect() and getting the object list.

I agree that it would be handy to obtain a list of tasklets directly from 
Stackless.  It has helped me in the past with real-time debugging.  Maybe 
Richard could let us in on how Eve does this, if at all.

- Dave