[Twisted-Python] Cancelling a pb callRemote

[Phil Mayers]

Is there any support, or any interest in / way to add support for 
deferred cancellation in pb?

Specifically I'd like do have something like:

class blah(pb...):
   def remote_somelongtask(self, args):
     ...
     taskid = somefunc()
     d = defer.Deferred(lambda : canceltask(taskid))
     return d

...and on the client:

d = callRemote('somelongtask', args)
...
# now we no longer need it
d.cancel()

...and have the cancel the server-side task.